If it's only few tickets from a project but you can edit others, it's probably related to workflow property set on the workflow for the status the issue is in.
Use workflow properties | Atlassian Support
Regards
Adding to what @Florian Bonniec said, if it's all issues within one/multiple projects, you may not have the Edit Issues permission in the permission scheme associated with those projects.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.
Online forums and learning are now in one easy-to-use experience.
By continuing, you accept the updated Community Terms of Use and acknowledge the Privacy Policy. Your public name, photo, and achievements may be publicly visible and available in search engines.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.