Count the number of the "Yes" results of a calculated measure month over month

[Shel Price]

I created a calculated measure (SOW Listed) that returns "Yes" or "No" if another field is populated properly (this field is calculated based on a property not a dimension). I need to calculate the number of "Yes" results for each month. I've looked at several similar questions that have been posted but haven't been able to tailor them to fit my need. 

    This one of the many things I've tried:

    Aggregate(
    --set of issues with matching custom field value Yes
    Filter(
    Descendants([Issue].CurrentHierarchyMember, [Issue].[Issue]),
    CoalesceEmpty([Measures].[SOW Listed],"") MATCHES "Yes"),

    [Measures].[Issues resolved])

    [Measures].[SOW Listed],"") MATCHES "Yes")

Tried changing the Aggregate to Count. The formula doesn't error out, but I get this error:

"Child process request failed with Net::ReadTimeout:
The child process will be restarted now, please retry the request in a minute."

This is the formula for SOW Listed: 

    IIf(Len([Measures].[Issue SOW Number]) > 3, "Yes","No")

Also getting this error:

"Child process request failed with EOFError: end of file reached"

Would greatly appreciate any help you can provide. I've got a few other measures I need to create like this (dependent on property rather than dimensions), so telling me how to work through this would be wonderful. Thanks in advance. 

[Shel Price]

By the way, our sys admin already increase out time out to 300.

[Anoop Wilson]

Did you solve this issue ?

[Shel Price]

Yes, see below.

Sum(
Filter(
Descendants([Issue].CurrentMember,[Issue].[Issue]),
[Measures].[SOW Listed] MATCHES "Yes"),
[Measures].[Issues resolved])