The CA certificate our OpenVPN setup uses was set to expire on Dec 22 2017, so we've had to generate a new one.
That means all members need to be using the latest one.

The configuration files at GitHub have already been updated with the new CA.

If you want to modify your existing configs manually, you can get the latest CA from

If you are using any widget before v3.12, you'll need to upgrade to the latest widget at (hashes available here)
Due to a bug in the self-updating code in versions before v3.12, the widget will NOT automatically upgrade to v3.12. You'll have to manually download/install it from the above link.
If you're still using v2.22, the updating code there will still work since that version just did a simple `start`, and setup.exe there has been updated to v3.12.