If the signing basically works. I.e. you don't get any error messages on signing and the extension works at first when the debugPlayer flag is set to 0, then probably one of these 3 are happening.
1) The Certificate has a problem like the number of days it was set to be valid for. Or for the country you did USA instead of US (or the other way round)
2) Something in the extension is causing a change to the contents of the extensions base directory.
3) An antivirus program is causing a change to the contents of the extensions base directory.
You could also try signing with a different timestamp, some are much less problematic than others.
See a list of options here. HTML Panel Tips #24: Fixing ZXP Timestamping errors | Photoshop, etc.
I think I was able to resolve my problem by:
1. Updating ZXPSign to the latest version
2. Getting rid of timestamp in signature
What do you mean by getting rid of the timestamp in the signature?
How did you set up the signature?
According to some posts I have found here, Adobe aren't sure themselves if `tsa` parameter is working properly for signatures.
There seem to be some issues with timestamp servers
Now I sign without tsa:
./ZXPSignCmd -sign build/cep dist/mypanel.zxp mypanel.p12 $password
Very interesting. I'll look into that, I wouldn't have thought that would work.
Keep us updated if you see a change (I.e. it stops working, which hopefully it won't)
There is big talk in the Adobe CEP team of dropping the whole need for signatures which are anyway almost completely meaningless.
Hopefully that could materialize with the next CEP