Can't sync - a network error occured

Every time I try to sync I get the error message seen in the attached image.

Any advice?

After exiting my VPN, the message changed to this.

Tried obvious things like restarting. Tried disabling VPN and antivirus. Tried disabling all add-ons. Problem solved by downgrading anki.

Problem returned this morning

Given the fact that you use a VPN and antivirus, they are the most likely culprits, but you may also want to try syncing over another network to rule out your local connection as the problem.