License key issues

[ShelCOYS]

Hi, I have fm 14 server running on a mac mini. I have recently upgraded to FM16 running Mojave on 2 x local macs. We started with one license, where only one of us could use FM at a time (as we knew), I have since bought another copy and and reinstalled FM16 on the local mac with the new serial number but the server still seems to think we are using the same copy?? and we are getting the attached error. I have completely uninstalled FM locally but still does not work. I have asked my FM guy, as well as 2 or 3 other people but everyone seems to be stumped?? Is there any way of clearer the cache which may be holding this old information? Any help would be much appreciated.