If you want to switch the mail service from hosting to an external mail service, for example, Gmail (GSuite/Google Workspace), Outlook.com, Yahoo Mail, Yandex or other, you need to follow a few simple steps.
This article shows an example of setting up Gmail (GSuite/Google Workspace).
1. Switching mail to an external service, you must disable the mail service in the hosting. To do this, log in to the hosting control panel, choose Mail section, then Mail Settings section.
2. Click on the domain name and disable the mail service - Activate mail service on this domain option:
https://www.screencast.com/t/Q6Zvst5ZH
3. Next, you need to make changes to the MX - and TXT-DNS records of your domain. DNS records management (A, MX, CNAME, TXT, etc) is available in the Hosting Control Panel (Plesk), section Websites & Domains - example.com - DNS Settings.
4. You need to remove the existing MX records for your domain:
https://www.screencast.com/t/yyuXrF4S
5. Next, you need to add 5 new MX records (only for Gmail):
alt1.aspmx.l.google.com/priority 5
alt2.aspmx.l.google.com/priority 5
alt3.aspmx.l.google.com/priority 10
alt4.aspmx.l.google.com/priority 10
6. Click - Add record button and add the first record from the list:
https://www.screencast.com/t/I1nZtu12B
Repeat the procedure for the remaining 4 MX records.
7. Next, you need to correct the TXT (SPF) record.
Find an entry in the TXT-DNS list which value begins with "v=spf1 ..." and open it to edit.
8. Replace the value of the TXT-DNS entry with the following:
"v=spf1 a mx include:relay.mailchannels.net include:_spf.google.com -all"
https://www.screencast.com/t/sQH0CxuFg
9. Apply all the changes made in the domain zone - Update button:
https://www.screencast.com/t/lQYY2vTmvzP
Changes will take effect within 1 hour.