How it is going? Have you found a fix for your issue or do you still need assistance?
Here are observations:
1. The error is clear.
2. The error occurs when the token is null.
Make sure the token is not null.
Please note, We are unable to troubleshoot & debug code for community support. If you are interested in further assistance, [check our VIP support packages](https://www.gluu.org/entitlements/) for more information.
Hope the suggestion will help you.