Failed to send mail using php mail function using MAMP PRO

Until several days, I conveniently send emails using the PHP mail function. but a few days ago I switched my ISP. and since then I can’t send any letters. I set the postfix configuration of outgoing mail to gmail.comand it gives me the following error in the log file.

   May  6 18:54:05 Ibrahim-Armars-MacBook-Pro postfix/smtp[1449]: connect to aspmx.l.google.com[74.125.53.27]:25: Operation timed out
    May  6 18:54:05 Ibrahim-Armars-MacBook-Pro postfix/smtp[1446]: connect to aspmx.l.google.com[74.125.53.27]:25: Operation timed out
    May  6 18:54:05 Ibrahim-Armars-MacBook-Pro postfix/smtp[1452]: connect to aspmx.l.google.com[74.125.53.27]:25: Operation timed out
    May  6 18:54:05 Ibrahim-Armars-MacBook-Pro postfix/smtp[1455]: connect to mx1.hotmail.com[65.55.92.184]:25: Operation timed out
    May  6 18:54:05 Ibrahim-Armars-MacBook-Pro postfix/smtp[1456]: connect to mx3.hotmail.com[65.55.92.136]:25: Operation timed out
    May  6 18:54:05 Ibrahim-Armars-MacBook-Pro postfix/smtp[1453]: connect to aspmx.l.google.com[74.125.53.27]:25: Operation timed out
    May  6 18:54:05 Ibrahim-Armars-MacBook-Pro postfix/smtp[1454]: connect to aspmx.l.google.com[74.125.53.27]:25: Operation timed out
May  6 18:56:05 Ibrahim-Armars-MacBook-Pro postfix/smtp[1454]: connect to aspmx3.googlemail.com[72.14.213.27]:25: Operation timed out
May  6 18:56:05 Ibrahim-Armars-MacBook-Pro postfix/smtp[1454]: warning: 11C203ECD84: defer service failure
May  6 18:56:05 Ibrahim-Armars-MacBook-Pro postfix/smtp[1454]: 11C203ECD84: to=<azhar@iarmar.com>, relay=none, delay=4504, delays=4353/0.13/150/0, dsn=4.4.1, status=deferred (connect to aspmx3.googlemail.com[72.14.213.27]:25: Operation timed out)
May  6 18:56:05 Ibrahim-Armars-MacBook-Pro postfix/smtp[1454]: connect to aspmx3.googlemail.com[72.14.213.27]:25: Operation timed out
May  6 18:56:05 Ibrahim-Armars-MacBook-Pro postfix/smtp[1454]: warning: 11C203ECD84: defer service failure
May  6 18:56:05 Ibrahim-Armars-MacBook-Pro postfix/smtp[1454]: 11C203ECD84: to=<azhar@iarmar.com>, relay=none, delay=4504, delays=4353/0.13/150/0, dsn=4.4.1, status=deferred (connect to aspmx3.googlemail.com[72.14.213.27]:25: Operation timed out)

what might cause the problem? do you think this is my new internet provider? I called customer service there, and, unfortunately, they do not know about it. what would be a possible solution for sending mail with php, I am using MAMP PRo 1.9.2.