since yesterday all my SIS files get rejected with the message
There is something wrong in the SIS file's Publisher ID signature. Please remove all the signatures from the SIS and resign with your Publisher ID.
I cleared and recompiled my code several times and also checked with signsis for the certificate of the sis file. I also downloaded the original file of an earlier accepted submission which got rejected, too. My publisher ID is valid until somewhere next year.

Can anyone give a hint what I could have missed?