Sorry, we were unable to save the latest changes to your design

Hello!

I am using Express on the latest version of Chrome (Windows 11 PC) to create a simple newsletter. When I opened my project today, I have tried making very simple changes (e.g. bolding a header, etc.). Problem is, after each change, I recieve the message: Sorry, we were unable to save the latest changes to your design. Please refresh the page or try again.

I've tried both options multiple times to no avail, have cleared my cache, have logged out and back in... I am at a loss for what to try next. Ideas??