You can find the ecp file here: c:\program files\esri\license10.0\sysgen\keycodes. This keycodes file can be opened in notepad and saved as a .ecp extension as a backup and can be used to reauthorize ArcGIS Server on the same machine. If you need to authorize ArcGIS Server on a different machine, you will need to authorize it against ESRI Customer Service the same way your first machine was initially authorized.
I have a two authorization numbers X/Y which could be used for arcgis server 10.5.1 for one server. However I am installing arcgis server 10.4.1 in another server and both X/Y could not be used. Any course of actions?
I have the same issue , so i contacted the distributor in my country and tell me the only way to do this is contact esri to reset the license for server . i don't know if this the best practice.if any one get the solution plz tell us