ERR_NGROK_6513: Failover backends may only contain up to MAX failover backends; you have VAL failover backends - ngrok documentation

What does ERR_NGROK_6513 mean?

ngrok returns ERR_NGROK_6513 with this message:

Failover backends may only contain up to <MAX> failover backends; you have <VAL> failover backends.

Where can I get more help with ERR_NGROK_6513?

Email support@ngrok.com and include the error code.