High Prefect Castor:
To become an Raider, the appropriate level and token are required. Your level must be at least 20 to qualify to change profession. You need a token to prove you have passed the Test of the Raider, as well.
it seems that you have passed the Test of the Raider, but your level is not high enough. Level 20 or higher is required to change profession. I cannot allow you to change profession if your level is not sufficient, even though you have a token. Come back when you have increased your level.