When we are trying to upload on-premise license file on AEUI facing below issue as ss.
Try out things below:
If tomcat is started as a service then, stop the service and try running tomcat manually and check if you are able to upload the license
MAC address detected in code for your system is blank. Please check if any system setting/permission is causing this issue
If it is a inhouse setup try changing server machine and then test this scenario again.