calendar not synching past certain date

one of my calendars isn’t synching (properly) … anyone have a some good advice?

eM Client 10.3.1738 (984d31d) on an older Win10 machine
several accounts (email / calendar / …)
same setup on two other PCs (one Win10, one Win 11 … neither has this problem)
difference here: not used in 4 weeks & on a cell phone hotspot (which can however pull 10-20Mbps).

If you have a 10-20mbps connection then it’s nothing to do with that.

If your other Win 11 PC’s with the same accounts setup do sync the same calendars ok and your Win 10 PC has no optionally installed firewall/security programs or antivirus program or VPN enabled “and is not getting any email or calendar data”, then could be your Windows 10 “cannot reach the License Server” so has deactivated and is not getting any data.

See extract from @Gary post below from the following thread.

https://forum.emclient.com/t/licenseserver-cant-be-reached-since-last-10-days/80922/4

"eM Client needs to periodically contact the license server to validate your license. If you have a firewall or VPN that is blocking the connection, then eM Client will eventually be disabled.

“Can you see if these links open in your web browser”:

https://licensing.emclient.com
https://licensemanager.emclient.com
http://emclient.com

“No need to login on the pages, just open them”

Now “if you can reach the License servers ok” with you Windows 10 machine and eM Client is showing activated ok via “Menu / Help / License” then could be you might possibly have a eg: corrupted account in eM Client and might then either need repairing or removing and readding.

So if it’s IMAP, Exchange, Office 365 or iCloud calendar, try “right clicking on the word Calendar” directly under your account, and then click “Properties” at the bottom. Then click the “Repair” tab at the top and click “Repair”. That will clear your local calendar cache in eM Client and resync your online calendar events locally.

Now if Repairing your calendar doesn’t make any difference, then go to “Menu / Accounts” and remove and readd your account via the automatic account wizard or manual option depending on your specific account setup and then save accounts and close and reopen eM Client and see if that updates your events.

Lastly if none of that makes any difference then “if you originally installed eM Client from the eM Client website”, then go to the release history page and try updating to the latest version 10.3.2412 just released recently and see if that fixes your calendar problem.

Note: Before repairing or removing and readding your account or before updating to the latest version, “make a manual backup first” via “Menu/Backup” incase you need to restore for any reason. You can see when the backup is complete in Show Operations via clicking the drop-down on the right of Refresh top left.