XD error 44:76

I can no longer share changes to a file I've previously shared with my clients. No matter which settings I specify, Development, Presentation or Design - with or without downloadable assets I get error 44:76.

The file is not large and every time I try to share it sits at 100% for about 5 minutes before giving me the error. I'm not using wifi but am hard wired, my connection is file and Im on the latest MacOS. I've logged out of my Adobe account and re-logged in.

This is the sencond client I've had that I can't show work to after being able to do so for the first 4-5 revs of a site. It's getting so bad that Im going to have to find an alternative to XD. I'm losing business!!

Please give me some suggestions of how to solve this.