Hi @dilmax, and welcome!
I’m not sure what would be necessary GUI-wise, but I can guide you through what I think will fix it with the CLI, which I suspect will also fix it in the GUI.
For that I think you’ll have to refresh your mirror pool and then force-update said databases:
- To refresh your mirror pool to the 5 fastest mirrors, based on your IP and thus location, run:
sudo pacman-mirrors --fasttrack=5 && sudo pacman -Syyu
- Then force-refresh the databases:
pamac update --force-refresh
Hope this helps!