My co author is not able to add link + makes links disappear when editing

Hello,

We are two working on the same website, and I can do everything well with your plugin, but on his side, he can’t edit my work without losing the links or he can’t even save a link attached to Hover plugin, what could be the issue? He has last version of browser, Chrome… Not sure how I can find an answer, he shared his screen and he does it the right way but it wont save.

Thanks,