The license located at config/license.key belongs to X I have an error appearing on my site:

This site is the production version of the site - before hand there was a staging version and a test version.
The test version (hosted on the same server, does not have this error).
So my question is how do I generate a new License? this is a solo version of craft btw not a pro.
I have deleted the license in config/license.key - hoping this would generate a new one and the problem would be over - a new license was generated but the message remains.
Any help would be great -
Thanks - W
Go into Utilities &gt; Caches &gt; Clear Caches. I can't remember exactly which cache, but try all of them (maybe untick the asset transforms ones so you don't unnecessarily regenerate transformed assets).