Apple Mail signature not working for just 1 mail address
hello,
I have several email addresses and wanted to change the signatures since PCist tell me that they see attachments. Well after deleting an old signature and creating new ones, I can send the new and old ones from any of my email addresses except from my main one. I've looked at the things that could be different for this email address but cannot find it. When I had one or more signature to this email account, I can select which one should appear in preferences but when I try to compose a new message, it opens a blank one with only the none button for signature. The only option is to edit signatures but no matter what, it doesn't show the changed. I've deleted and reimported the .plists, deleted and reinstated the account, activated and deactivated iCloud drive... I just haven't found a solution, so far.
On my other older macbook pro, where I have the same email with a pop account, there ist no such problem. Any ideas? I would really appreciate some help.