To add, please go through the steps mentioned below:
1. Open the DNS setting on the dashboard of your domain provider.
2. Add this MX record here:
Type: MX
Name: Domain
Mailserver: mx.stackmail.com
Ex: –

3. SPF Record:
{Your domain.com} TXT v=spf1 include:spf.stackmail.com a mx -all

4. Now you need to add DKIM and DMARC records for sending and receiving emails with Gmail.
For DKIM and DMARC, check this:

Go through the demo video mentioned below:
Note–
- Now allow up to 48 hours. DNS propagation time varies according to your domain provider.
- If you are still experiencing issues sending or receiving emails, please delete the email-related DNS entry, or you can also ask support.