Here are the recommended ways to turn off DMARC for your domain.
Note: If you can't turn off DMARC by following these steps, contact your domain provider. Google doesn't provide support for issues with your domain host.
Update your DMARC policy at your domain provider
Step 1. Change your policy record
Change your DMARC policy to p=none. A none policy means receiving servers won't take action on messages from your domain that don't pass either SPF or DKIM.
When your DMARC policy is none, you'll still receive daily DMARC reports. To turn off DMARC reports, remove the rua tag from your DMARC TXT record.
For more information on DMARC policy format and tags, go to Define your DMARC policy.
Step 2. Update the record at your domain provider
Then update the DMARC TXT record at your domain provider with the changes by following the steps in Add your DMARC record.
Remove the DMARC TXT record at your domain provider
Another way to turn off DMARC is to delete the DMARC DNS TXT record for your domain, at your domain provider. Refer to the steps in Add your DMARC record.