ERR_NGROK_5112: Event Destination "ID" cannot be deleted because it is still in use by at least one Event Stream - ngrok documentation

What does ERR_NGROK_5112 mean?

ngrok returns ERR_NGROK_5112 with this message:

Event Destination "<ID>" cannot be deleted because it is still in use by at least one Event Stream

Where can I get more help with ERR_NGROK_5112?

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