Codes don’t work

My apprentice master codes are not working. I have tried a variety of codes from people and none work. It says code not accepted or valid however they’ve worked in the past. How do I rectify this ?

Codes are different for different servers, make sure you are applying code of the correct server.

They also might have 30 apprentices, after that the code will not work.

I have the same issue - There should really be a note that they need to be on the same server

For me, the issue is the first letter has to be lower case, but mine kept auto putting in upper case. If everything is lower case, you should be fine. Or just use a master code like mine with a number at the front: 7wken