Setting APN username on TK102B

When sending apnuser123456 internet I get password err!
*internet is the apn username. What’s could be the issue?

I also tried up123456 internet but I get nothing back.

I would guesse Wrong password with password err!

Isnt it: APN123456

https://www.munstergps.ie/wp-content/uploads/TK102B-Manual.pdf

Apn123456 I get apn ok!
But then apnuser123456 I get password err!

Well I maybe don’t need the user anyway. I have two documentations one is with the other without. I just checked a friends phone with the same provider and they don’t use the username.

Well the actual problem is that gprs123456 gives me back gprs ok! But when I send check123456 it shows it is still off.