ERR_NGROK_SHIP_POOL_PROVIDER_READ_UNAVAILABLE: PROVIDER did not answer the request to OPERATION: REASON - ngrok documentation

What does ERR_NGROK_SHIP_POOL_PROVIDER_READ_UNAVAILABLE mean?

ngrok returns ERR_NGROK_SHIP_POOL_PROVIDER_READ_UNAVAILABLE with this message:

<PROVIDER> did not answer the request to <OPERATION>: <REASON>

Where can I get more help with ERR_NGROK_SHIP_POOL_PROVIDER_READ_UNAVAILABLE?

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