Is this related to a UCC-specific error or warning message? If so, please provide details of the issue you're having.
If not, unfortunately this is a Unity-specific question and as such this isn't the right forum - I'm sure someone over at the Unity support forums would be able to help.
A quick search found this page which may be of interest:
https://docs.unity3d.com/Manual/DomainReloading.html