Issue: VS403221 The value ‘-1’ is not an allowed value for field ‘Priority’. Valid values are 1, 2, 3, 4.
Solution : This issue specifically occurs whenever you have added some custom values to Priority field for any workitem. There are 2 ways in which you can fix it either by making the priority values again as 1,2,3,4 or having a default value for priority. If you don’t have a default value for priority then it will be assigned -1 which will trigger this error. So have a default value for priority whenever you are making a copy of the process template.