What causes a failure when checking the relevance of the mail server?

Question

PHP

I use the function of checking the validity of the email address. Gives error 110 when trying to open a socket, what should I do?

Answer 1

110 error is Connection timed out.
Looks like you're sending somewhere wrong.
PS I may not understand something, but it seems to me that this code is hellishly redundant for checking email.