Check your AVAST for a feature called RealSite, which will have your laptop use a DNS server owned and operated by AVAST in addition to Pi-hole. It's worth noting that you may expose your DNS history to AVAST this way.
Normally, we receive complaints about RealSite providing DNS resolution for domains blocked by Pi-hole (see e.g. Hilfe: Windows löst Hostname auch ohne PiHole auf? - #26 by Chris80).
But if their DNS server is down or you have blocked access to their server, then DNS resolution may also fail in circumstances.
Try disabling AVAST RealSite and see if this solves your issue.