Edit item on Kanban board returns 400 and locks up

[Dan Mihai]

1. Select "Kanban Board" from the left side menu
2. Click on any of the cards on the board. The card (issue) details open on the right side of the board in a panel.
3. Click on the panel's three little dots in the upper-right corner and select "Edit"
4. A modal/popup should open with the issue details, but instead the request sent to the server gets a 400 response. You can see this in Chrome DevTools -> Console.
5. When this blockage occurs, refreshing the page does not help get the board back, you must select "Boards" in the top menu and select the Kanaban board again to display the board and the main side menu. Otherwise you will be left with a skeleton loader and a broken page.

Other way to reproduce the issue:

1. Open an Epic's detail page
2. Click on the "Edit" button on the left of the top toolbar
3. Notice the spinner appears but the issue (Epic) details modal/popup is not opening
4. Notice the errors in Chrome DevTools console
5. Refreshing the page after the error occurs doesn't help, you have to select "Boards" in the top menu and click on "medCloud POC" to display the Epic details page again.

Server information:

- Windows Server 2019 / SQL Server 2017 / 16 Gb RAM / 4TB SSD / 8 cores

- SSL using IIS reverse proxy (IIS + URL Rewrite + ARR3)

Google Chrome reports a 400 (aborted, bad request) error in an attempt to redirect to ".../batch.js" in RapidBoard.jspa in the following code block:

try {
/* module-key = 'com.atlassian.plugins.atlassian-plugins-webresource-rest:curl', location = 'js/wrm/lib/curl-0.7.3.js' */
(function(a){var P="0.7.3",u="curl",p="define",G,v,g,d=a.document,l=d&&(d.head||d.getElementsByTagName("head")[0]),V=l&&l.getElementsByTagName("base")[0]||null,i={},N={},c={},A="addEventListener" in a?{}:{loaded:1,complete:1},m={},b=m.toString,y,k={},f={},h=false,O,t=/\?|\.js\b/,e=/^\/|^[^:]+:\/\//,L=/(\.)(\.?)(?:$|\/([^\.\/]+.*)?)/g,E=/\/\*[\s\S]*?\*\/|(?:[^\\])\/\/.*?[\n\r]/g,C=/require\s*\(\s*["']([^"']+)["']\s*\)|(?:[^\\]?)(["'])/g,M,x;function Q(){}function D(X,W){return b.call(X).indexOf("[object "+W)==0}function B(X){var W;X.path=J(X.path||X.location||"");W=X.main||"./main";if(!n(W)){W="./"+W}X.main=s(W,X.name+"/");X.config=X.config;return X}function n(W){return W.charAt(0)=="."}function j(W){return e.test(W)}function o(X,W){return J(X)+"/"+W}function J(W){return W&&W.charAt(W.length-1)=="/"?W.substr(0,W.length-1):W}function s(ab,X){var ac,W,Z,Y,aa;ac=1;W=ab;if(n(W)){Y=true;W=W.replace(L,function(ad,ae,af,ag){if(af){ac++}return ag||""})}if(Y){Z=X.split("/");aa=Z.length-ac;if(aa<0){return ab}Z.splice(aa,ac);return Z.concat(W||[]).join("/")}else{return W}}function S(X){var W=X.indexOf("!");return{resourceId:X.substr(W+1),pluginId:W>=0&&X.substr(0,W)}}function U(){}function z(X,W){U.prototype=X||m;var Z=new U();U.prototype=m;for(var Y in W){Z[Y]=W[Y]}return Z}function F(){var X,aa,W;X=this;aa=[];function ab(ac,ad,ae){aa.push([ac,ad,ae])}function Y(ag,ad){var af,ac,ae=0;while((af=aa[ae++])){ac=af[ag];if(ac){ac(ad)}}}W=function Z(ad,ac){ab=ad?function(ae,af){ae&&ae(ac)}:function(ae,af){af&&af(ac)};W=Q;Y(ad?0:1,ac);Y=Q;aa=y};this.then=function(ac,ad,ae){ab(ac,ad,ae);return X};this.resolve=function(ac){X.resolved=ac;W(true,ac)};this.reject=function(ac){X.rejected=ac;W(false,ac)};this.progress=function(ac){Y(2,ac)}}function r(W){return W instanceof F}function H(W,Z,X,Y){if(r(W)){return W.then(Z,X,Y)}else{return Z(W)}}function q(Y,X,Z){var W;return function(){if(--Y>=0&&X){W=X.apply(y,arguments)}if(Y==0&&Z){Z(W)}return W}}x={toAbsId:function(ab,aa,W){var Y,X,Z;Y=s(ab,aa);if(n(Y)){return Y}Z=S(Y);X=Z.pluginId;Y=X||Z.resourceId;if(Y in W.pathMap){Y=W.pathMap[Y].main||Y}if(X){if(X.indexOf("/")<0&&!(X in W.pathMap)){Y=o(W.pluginPath,X)}Y=Y+"!"+Z.resourceId}return Y},createContext:function(W,X,ab,aa){var Z;Z=new F();Z.id=X||"";Z.isPreload=aa;Z.depNames=ab;Z.config=W;function ad(ae){return x.toAbsId(ae,Z.id,W)}function ac(ae){return x.resolvePathInfo(ad(ae),W).url}function Y(ag,ak,af){var ae,aj,ai,ah;ae=ak&&function(){ak.apply(y,arguments[0])};if(D(ag,"String")){if(ae){throw new Error("require(id, callback) not allowed")}aj=ad(ag);ai=k[aj];if(!(aj in k)){throw new Error("Module not resolved: "+aj)}ah=r(ai)&&ai.exports;return ah||ai}else{H(x.getDeps(x.createContext(W,Z.id,ag,aa)),ae,af)}}Z.require=Y;Y.toUrl=ac;Z.toAbsId=ad;return Z},createResourceDef:function(W,ad,ab){var aa,X,Z;aa=x.createContext(W,ad,y,ab);X=aa.resolve;Z=q(1,function(af){aa.deps=af;try{return x.executeDefFunc(aa)}catch(ae){aa.reject(ae)}});aa.resolve=function Y(ae){H(ab||h,function(){X((k[aa.id]=f[aa.url]=Z(ae)))})};aa.exportsReady=function ac(ae){H(ab||h,function(){if(aa.exports){Z(ae);aa.progress(N)}})};return aa},createPluginDef:function(W,aa,Z,Y){var X;X=x.createContext(W,Z,y,Y);return X},getCjsRequire:function(W){return W.require},getCjsExports:function(W){return W.exports||(W.exports={})},getCjsModule:function(X){var W=X.module;if(!W){W=X.module={id:X.id,uri:x.getDefUrl(X),exports:x.getCjsExports(X),config:function(){return X.config}};W.exports=W.exports}return W},getDefUrl:function(W){return W.url||(W.url=x.checkToAddJsExt(W.require.toUrl(W.id),W.config))},setApi:function(W){var Y,Z,X,aa,ab,ac;Y=u;Z=p;X=aa=a;ab=" already exists";if(W){ac=W.overwriteApi||W.overwriteApi;Y=W.apiName||W.apiName||Y;X=W.apiContext||W.apiContext||X;Z=W.defineName||W.defineName||Z;aa=W.defineContext||W.defineContext||aa;if(v&&D(v,"Function")){a[u]=v}v=null;if(g&&D(g,"Function")){a[p]=g}g=null;if(!ac){if(X[Y]&&X[Y]!=K){throw new Error(Y+ab)}if(aa[Z]&&aa[Z]!=I){throw new Error(Z+ab)}}}X[Y]=K;aa[Z]=I},config:function(aa){var ab,Z,W,X;if("baseUrl" in aa){aa.baseUrl=aa.baseUrl}if("main" in aa){aa.main=aa.main}if("preloads" in aa){aa.preloads=aa.preloads}if("pluginPath" in aa){aa.pluginPath=aa.pluginPath}if("dontAddFileExt" in aa||aa.dontAddFileExt){aa.dontAddFileExt=new RegExp(aa.dontAddFileExt||aa.dontAddFileExt)}ab=G;Z=z(ab,aa);Z.pathMap=z(ab.pathMap);W=aa.plugins||{};Z.plugins=z(ab.plugins);Z.paths=z(ab.paths,aa.paths);Z.packages=z(ab.packages,aa.packages);Z.pathList=[];function ac(af,am){var ah,aj,al,ak,an,ai;for(var ag in af){al=af[ag];if(D(al,"String")){al={path:af[ag]}}al.name=al.name||ag;an=Z;ak=S(J(al.name));ah=ak.resourceId;aj=ak.pluginId;if(aj){an=W[aj];if(!an){an=W[aj]=z(Z);an.pathMap=z(Z.pathMap);an.pathList=[]}delete af[ag]}if(am){ai=B(al);if(ai.config){ai.config=z(Z,ai.config)}}else{ai={path:J(al.path)}}ai.specificity=ah.split("/").length;if(ah){an.pathMap[ah]=ai;an.pathList.push(ah)}else{an.baseUrl=x.resolveUrl(al.path,Z)}}}function ad(af){var ag=af.pathMap;af.pathRx=new RegExp("^("+af.pathList.sort(function(ai,ah){return ag[ah].specificity-ag[ai].specificity}).join("|").replace(/\/|\./g,"\\$&")+")(?=\\/|$)");delete af.pathList}ac(aa.packages,true);ac(aa.paths,false);for(X in W){var Y=x.toAbsId(X+"!","",Z);Z.plugins[Y.substr(0,Y.length-1)]=W[X]}W=Z.plugins;for(X in W){W[X]=z(Z,W[X]);var ae=W[X].pathList;if(ae){W[X].pathList=ae.concat(Z.pathList);ad(W[X])}}for(X in ab.pathMap){if(!Z.pathMap.hasOwnProperty(X)){Z.pathList.push(X)}}ad(Z);return Z},checkPreloads:function(W){var X;X=W&&W.preloads;if(X&&X.length>0){H(h,function(){h=x.getDeps(x.createContext(G,y,X,true))})}},resolvePathInfo:function(Z,X){var Y,ab,aa,W;Y=X.pathMap;if(!j(Z)){aa=Z.replace(X.pathRx,function(ac){ab=Y[ac]||{};W=ab.config;return ab.path||""})}else{aa=Z}return{config:W||G,url:x.resolveUrl(aa,X)}},resolveUrl:function(Y,W){var X=W.baseUrl;return X&&!j(Y)?o(X,Y):Y},checkToAddJsExt:function(X,W){return X+((W||G).dontAddFileExt.test(X)?"":".js")},loadScript:function(Z,ab,X){var Y=d.createElement("script");function aa(ac){ac=ac||a.event;if(ac.type=="load"||A[Y.readyState]){delete c[Z.id];Y.onload=Y.onreadystatechange=Y.onerror="";ab()}}function W(ac){X(new Error("Syntax or http error: "+Z.url))}Y.onload=Y.onreadystatechange=aa;Y.onerror=W;Y.type=Z.mimetype||"text/javascript";Y.charset="utf-8";Y.async=!Z.order;Y.src=Z.url;c[Z.id]=Y;l.insertBefore(Y,V);return Y},extractCjsDeps:function(X){var Y,W=[],Z;Y=typeof X=="string"?X:X.toSource?X.toSource():X.toString();Y.replace(E,"").replace(C,function(aa,ac,ab){if(ab){Z=Z==ab?y:Z}else{if(!Z){W.push(ac)}}return""});return W},fixArgs:function(X){var ac,aa,Y,ab,W,Z;W=X.length;Y=X[W-1];ab=D(Y,"Function")?Y.length:-1;if(W==2){if(D(X[0],"Array")){aa=X[0]}else{ac=X[0]}}else{if(W==3){ac=X[0];aa=X[1]}}if(!aa&&ab>0){Z=true;aa=["require","exports","module"].slice(0,ab).concat(x.extractCjsDeps(Y))}return{id:ac,deps:aa||[],res:ab>=0?Y:function(){return Y},cjs:Z}},executeDefFunc:function(Y){var X,W;W=Y.cjs?Y.exports:y;X=Y.res.apply(W,Y.deps);if(X===y&&Y.exports){X=Y.module?(Y.exports=Y.module.exports):Y.exports}return X},defineResource:function(X,W){X.res=W.res;X.cjs=W.cjs;X.depNames=W.deps;x.getDeps(X)},getDeps:function(X){var ab,af,ai,ad,ag,aa,W,aj,ah;ai=[];af=X.depNames;ad=af.length;if(af.length==0){Y()}function ae(am,ak,al){ai[ak]=am;if(al){aj(am,ak)}}aj=q(ad,ae,ac);ah=q(ad,ae,Y);for(ab=0;ab<ad;ab++){W=af[ab];if(W in M){ah(M[W](X),ab,true);if(X.exports){X.progress(i)}}else{if(!W){ah(y,ab,true)}else{Z(W,ab)}}}return X;function Z(am,al){var an,ak,ap,ao;an=q(1,function(aq){ak(aq);ah(aq,al)});ak=q(1,function(aq){aj(aq,al)});ap=x.fetchDep(am,X);ao=r(ap)&&ap.exports;if(ao){ak(ao)}H(ap,an,X.reject,X.exports&&function(aq){if(ap.exports){if(aq==i){ak(ap.exports)}else{if(aq==N){an(ap.exports)}}}})}function Y(){X.resolve(ai)}function ac(){X.exportsReady&&X.exportsReady(ai)}},fetchResDef:function(W){x.getDefUrl(W);x.loadScript(W,function(){var X=O;O=y;if(W.useNet!==false){if(!X||X.ex){W.reject(new Error(((X&&X.ex)||"define() missing or duplicated: "+W.url)))}else{x.defineResource(W,X)}}},W.reject);return W},fetchDep:function(ai,X){var W,Z,ae,ab,ah,ad,aa,aj,af,Y,ac,ag;W=X.toAbsId;Z=X.isPreload;ae=X.config||G;ab=S(W(ai));aj=ab.resourceId;ah=ab.pluginId||aj;af=x.resolvePathInfo(ah,ae);if(ab.pluginId){ad=ah}else{ad=af.config.moduleLoader||af.config.moduleLoader;if(ad){aj=ah;ah=ad;af=x.resolvePathInfo(ad,ae)}}if(ah in k){Y=k[ah]}else{if(af.url in f){Y=k[ah]=f[af.url]}else{Y=x.createResourceDef(af.config,ah,Z);Y.url=x.checkToAddJsExt(af.url,af.config);k[ah]=f[af.url]=Y;x.fetchResDef(Y)}}if(ah==ad){ac=new F();ag=ae.plugins[ad]||ae;H(Y,function(am){var ao,ak,an;an=am.dynamic;if("normalize" in am){aj=am.normalize(aj,W,Y.config)||""}else{aj=W(aj)}ak=ad+"!"+aj;ao=k[ak];if(!(ak in k)){ao=x.createPluginDef(ag,ak,aj,Z);if(!an){k[ak]=ao}var al=function(ap){ao.resolve(ap);if(!an){k[ak]=ap}};al.resolve=al;al.reject=al.error=ao.reject;am.load(aj,ao.require,al,ag)}if(ac!=ao){H(ao,ac.resolve,ac.reject,ac.progress)}},ac.reject)}return ac||Y},getCurrentDefName:function(){var W;if(!D(a.opera,"Opera")){for(var X in c){if(c[X].readyState=="interactive"){W=X;break}}}return W}};M={require:x.getCjsRequire,exports:x.getCjsExports,module:x.getCjsModule};function K(){var X=[].slice.call(arguments),W;if(D(X[0],"Object")){W=X.shift();R(W)}return new w(X[0],X[1],X[2])}function R(W){if(W){x.setApi(W);G=x.config(W);x.checkPreloads(W);if("main" in W){setTimeout(function(){var X;X=x.createContext(G,y,[].concat(W.main));x.getDeps(X)},0)}}}function w(Y,ab,X,aa){var Z,W;W=x.createContext(G,y,[].concat(Y));this["then"]=Z=function(ac,ad){H(W,function(ae){if(ac){ac.apply(y,ae)}},function(ae){if(ad){ad(ae)}else{throw ae}});return this};this["next"]=function(ae,ac,ad){return new w(ae,ac,ad,W)};this["config"]=R;if(ab||X){Z(ab,X)}H(aa,function(){x.getDeps(W)})}K.version=P;K.config=R;function T(W){var Z,X,Y;Z=W.id;if(Z==y){if(O!==y){O={ex:"Multiple anonymous defines in url"}}else{if(!(Z=x.getCurrentDefName())){O=W}}}if(Z!=y){X=k[Z];if(!(Z in k)){Y=x.resolvePathInfo(Z,G);X=x.createResourceDef(Y.config,Z);k[Z]=X}if(!r(X)){throw new Error("duplicate define: "+Z)}X.useNet=false;x.defineResource(X,W)}}function I(){var W=x.fixArgs(arguments);T(W)}I.amd={plugins:true,jQuery:true,curl:P};G={baseUrl:"",pluginPath:"curl/plugin",dontAddFileExt:t,paths:{},packages:{},plugins:{},pathMap:{},pathRx:/$^/};v=a[u];g=a[p];if(!v||D(v,"Function")){x.setApi()}else{a[u]=y;R(v)}k[u]=K;k["curl/_privileged"]={core:x,cache:k,config:function(){return G},_define:T,_curl:K,Promise:F}}(this.window||(typeof global!="undefined"&&global)||this));
}catch(e){WRMCB(e)};
;

[Dan Mihai]

Upon further investigation, found that the culprit was ARR which adds additional headers pushing the MaxRequestBytes beyond the Atlassian recommended limit.

Got it fixed by maxing out BOTH the MaxFieldLength and MaxRequestBytes registry settings as described in the article below (followed by a server reboot to apply).

https://docs.microsoft.com/en-US/troubleshoot/iis/httpsys-registry-windows 

Hope this helps someone else encountering this hard to troubleshoot error.