My own signature shows as invalid

I have signed documents before without any issues. I was also able to easily clear my signature when necessary. I was able to do these steps before and after the issue I am describing below.

Issue: When trying to save my signature on a document, I got the following error message:

After this, my signature was somehow saved on the document, but is showing as an invalid signature. Thus, I can clear/delete it and nobody, including myself, can edit this document.

HELP!

Thank you!