ERR_NGROK_SHIP_POOL_AWS_REGION_UNSUPPORTED: The 'region' value REGION is not an AWS region code like 'us-east-1' - ngrok documentation

What does ERR_NGROK_SHIP_POOL_AWS_REGION_UNSUPPORTED mean?

ngrok returns ERR_NGROK_SHIP_POOL_AWS_REGION_UNSUPPORTED with this message:

The 'region' value <REGION> is not an AWS region code like 'us-east-1'.

Where can I get more help with ERR_NGROK_SHIP_POOL_AWS_REGION_UNSUPPORTED?

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