A simple notepad of stuff I might have included as answers if I was able:

• https://stackoverflow.com/questions/58215104/whats-the-neterr-http2-protocol-error-about Encountered this issue with nginx: use of "add_header" like add_header X-Example-Example "example, example, example,..."; can cause this error in nginx if you include a VT (CR or LF) as a char in the quoted header.