Can't update if the main repo is broken

• Device OS and version: Android 8.1
• Device model/manufacturer: Samsung galaxy S7
• F-Droid version (in the About screen): 1.12
• F-Droid privileged extension version (if installed): no

What did you do? (clear steps if possible)

Update from repositories

What did you expect to see?

Apps updating

What did you see instead?

Since the main repository encounters a server error, the update process try during a long long time without possibility to interrupt it. And when it finally stops, i disabled the main repository, hoping that it would use the mirrors instead, but it didn't, it keeps using the repo i had disabled.