Signature synced with GMail - how to get rid off it

In my signature list appears a signature with “synced with gmail”. I tried everything to get rid off that signature, but I’m unable to delete it. I have not the permission to delete it in emClient and after deleting it in GMail (web) it apppears after a short time :frowning:
Do you have any idea, how this problem can be solved?
emclient Version 10.1.4588