Problem description:
Some people fail to receive "test2". Why?
Well if your using world.Export() to send data to players with there own world, they need to be hosting there world on the port you picked when you sent the data. If there not hosting the world the message will never get there. You should really give more detail as to what your actually trying to do.
I believe that for a faster (or at least cleaner) communication here, you can use return "?test2" rather than calling world.Export() again. Also, try using findtext(), maybe there are some extra characters in T we don't know about.
In response to CaptFalcon33035
No, there aren't any extra characters, I checked if if() is true and it is.
In response to Soldierman
They are hosting world as [Addr] format is IP:Port I did testing on that. The server (which has provided code) is working currently and successfully receives messages. I am running server, then run other world, click verb, server does receive and reply successfully, and other world successfully receives reply. However when some other people host world (non-server) they don't receive reply, but sending is successful.