There is no problem when using the computer, but it will fail when using mobile browsers (including Android and Apple built-in browsers) or through FB/LINE embedded web pages on mobile phones. The following is my website behavior. The website requires authorization for the fan page. After clicking send_to_messenger,
Original estimate: Ask FB to log in. After logging in, confirm authorization and return to the website. Actual situation: After logging in and authorizing, you directly enter the FB page or the error message in the picture appears.
After checking, it was confirmed that the authorization was indeed unsuccessful. I would like to ask how to troubleshoot this problem.