Avast Business AV Pro - reactivation fails

Hello,
we have Avast Business Pro deployed on a few clients (non managed). License expired, has been renewed for another two years apparently.
When entering the “new” license code (same as before), it shows that the old license on this computer is expired but I can switch to this new license, which says something “Avast Business Pro Managed”.
When I try to switch to this renewed license, it works for a few seconds then says, something went wrong, and I’m stuck with the expired license and can’t use the new one. (Computer restarted and things like that, nothing helped.)
Do I need to remove and reinstall Avast or something? (I don’t want to do that!) or change to this “Managed” version or what?

Did you buy from Avast directly or from a reseller…?

I didn’t buy it - my boss did. He just gave me a printout of the email (with the “new” license key). It seems to be bought directly from avast.

Contact Business Sales: https://www.avast.com/business-sales.php