ERR_NGROK_5317: The SAML module for the edge route "RTEID" disallows IdP-initiated logins - ngrok documentation

What does ERR_NGROK_5317 mean?

ngrok returns ERR_NGROK_5317 with this message:

The SAML module for the edge route "<RTEID>" disallows IdP-initiated logins.

Where can I get more help with ERR_NGROK_5317?

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