Before we go ahead and help user how to fix Quickbooks error 3371 We will request them to first understand how this error occur, this normally happens when Entitlement client File gets damaged or corrupted in Quickbooks Software or Folder, this normally happens due to Power failure , Windows updates or it might also get damaged if your Antivirus is blocking necessary updates while updates are running. To Get this Error Fixed there are few Possible ways to Resolve
1. Restart your Machine
2. Try to take Quickbooks updates if not updated
3. Check if your Windows has Any update pending
4. Repair Quickbooks Software Installation.
Above are the steps to fix the Problem , if it doesn’t work than will request user not to take any more steps , just Call Quickbooks Support Executive @ 1-855-441-4436.