I think I found the problem.
In NordVPN preferences there is a feature called CyberSec that blocks ads and malware; I had it checked.
Previously it did not interfere with EN, but either something in EN 7.12 changed that caused it to be flagged by CyberSec, or NordVPN changed something in CyberSec that erroneously flagged EN.
After unchecking this feature, EN is now able to sync while I'm connected to the VPN.
For anyone else using NordVPN that has the same issue, try turning off CyberSec.