What version is your ArcGIS Server?
If it is ver. 10.5, then it would not accept a PRVC/ECP file of 10.1-10.4.x.
You need to authorize ArcGIS Server 10.5 with a fresh license code/ECP file generated from ver.10.5 only.
Did you allocate it on another machine (i.e. are you moving to a new machine). For example, it you had 10.3.x installed on another machine, and starting fresh with 10.4.1 on a new machine, you need to deauthorize it first. You can only authorize ArcGIS Server once. Check out your myesri page to see if the authorization still says 1/1 or if it is 0/1.
Not sure if an ECP file of ArcGIS Enterprise 10.5 will work for 10.4.1.
Earlier the ECP file for 10.1-10.4.x were similar, but in 10.5 it has changed.
Please check with your local Esri Tech Support to work closely on this issue.