Emails to Gmail get bounced with one of the errors below:
This message does not pass authentication checks (SPF and DKIM both 550-5.7.26 do not pass). SPF check for [example.com] does not pass with ip: 550-5.7.26 [203.0.113.2].
The MAIL FROM domain [example.com] has an SPF record with a\n5.7.26 hard fail policy (-all) but it fails to pass SPF checks with the ip:\n5.7.26 [203.0.113.2].
The IP address from the error is not allowed to send email on behalf of the domain. According to the official Gmail, "if third-party senders aren't included in the SPF record, messages sent from these providers are more likely to be marked as spam".
To solve this problem we need to add a SPF record on the DNS-zone of your domain.
Login to your panel through https://control.metaregistrar.com/
On your left menu, select Domains > search domains.
We need to find the domain of the emails that are not able to send emails to Gmail addresses.
If you have more than one domain, you can check and follow the steps for all of them.
Once you find your domain, click in DNS:
Then we need to EDIT:
Since the template is ready, and we don't need to write anything, click on APPLY TEMPLATES:
Select SPF, click to apply template, and this window will close. You are back to the DNS zone, and then just need to SAVE the changes!
Your email will work again in maximum 2h.