Windows Client Won't Connect to My Server

I migrated servers and now nextcloud desktop (win10) won’t connect to my server saying

“Failed to connect to NextCloud at https://sub.domain.com; Connection Refused”.

It’s been over 18 hours since the last DNS change. I looked up domain and all records seem OK.

I can log in to my nextcloud (web) just fine. I’m guessing the desktop client is still picking up the old certificate. I’ve already tried reinstalling the client. Is it possible to clear HSTS/FlushDNS for the client? Thanks!

I figured it out. It connected fine when I turned off my VPN.