Hi Lars, we are getting the error message like

'The URL couldn't be validated. Callback verification failed with the following errors: curl_errno = 35; curl_error = OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to domain:port ; HTTP Status Code = 200; HTTP Message = Connection established'.

… on your end. Also try to search for the Curl error, which is most likely related to a SSL config issue on your end.

SSL is working fine, it is provided by 'GO DADDY'

Debug it on your end

I'm facing the same error and also using ngrok...

same here, no official communication on why ngrok is blocked

Same here. I am configuring a webhook for the first time. I managed to create the Ngrok free URL, and I can access it through the browser. However, "verify and save" on the Meta for Developers website has no effect and gives this error. There is no other information. I am guessing it is some security issue that doesn't even try to access the URL at ngrok-free . app.

ngrok-free . app is blocked by FB, so don't use it.

I'm having the same issue with webhook, even apps deployed on Glitch, vercel is returning the same error which was not so few months ago.

I'm sure this is n update bug, I hope Facebook support will look into this

So i was able to resolve it using port forwarding feature on VS code, i forwarded the port and changed the visibility to public

same issue