I got "The server was unable to save the form at this time. Please try again.” error when I was trying to save new SharePoint list item.
After some troubleshooting found that this issue is closely related to server memory; when a server memory drops below certain level that is we get these type of errors. We can fix this error by making some memory to free by restarting/killing unused processes.
Permanent Fix
Add more memory (RAM) to resolve this issue permanently!
As for temporary workaround, you can try these solutions.
- Monitor your Server RAM usage. Try closing some programs running on the server.
- Restart"Search Host Controller Service" service in Services console ( services.msc).

Reference
www.sharepoint.diary.com

Munna LulPosted May 23, 2020, 5:01 AM
Did you try to add sharepoint to file explorer. https://www.windowsclassroom.com
Sean AchimPosted Aug 16, 2017, 2:58 AM
None of these worked for me. An interesting thing is that another site on a seperate subdomain on the same farm allows list data to be added or edited. this appears to be related to some of my sites only.
Rupali ShindePosted Oct 21, 2015, 6:54 AM
thanks got my issue resolved..