I have a board with a lot of components and traces. It loads and saves fine.
However, if I add some more components (about 30 in this case), while the PCB loads and edits normally, when I attempt to save it, I get a "Cannot connect to server" popup.
This message is misleading because the server is up and active (I can save other PCBs in other tabs). There's something about the complexity of the board (or perhaps the sheer size) that is causing the server to respond anomalously. I am able to save the JSON to a local file - it's 7.2MB long!
If there is a limit, it would be nice if the error message let you know what the problem actually is. It would be nicer if the PCB editor let you know when you were getting close to the limit.
If you need more information, let me know. I can probably rig up a project that demonstrates the problem (perhaps with the extra components set with Convert to PCB = No so you can just toggle them on and off). Obviously, I can't point you to a project that contains a PCB that can't be saved, because I can't save the PCB (hahahah!)
Best, Robert
Chrome
81.0.4044.138
OS X
10_15_4
EasyEDA
6.3.43