After my domain and hosting were transferred to another hosting company, some emails were not received by my mail accounts which are using G Suite as mail server.
Sender received this email after the sending email was bounced back.
The response was:
550 Please turn on SMTP Authentication in your mail client.
mail-it0-f50.google.com [209.85.214.50]:53804 is not
permitted to relay through this server without authentication.
I have configured the MX record, and the emails are up and running. However some emails are not received by us. I am wondering if this issue is related to us (maybe SPF record) or to the sender?
Best Answer
At first check your domain https://toolbox.googleapps.com/apps/checkmx/ Check your DNS zone MX, A and txt (sfp) records.
If you have recently changed DNS domains, check out DNS propagation, eg here: https://www.whatsmydns.net
Sometimes propagation time can last from 24 to 72 hours