We don’t recommend turning off SPF for your domain. If you’ve set up SPF and your messages are still being marked as spam, the cause could be something other than SPF. To identify the problem and try recommended solutions, follow the steps in Troubleshoot SPF issues.
If you’re not able to identify or fix the issue, contact Google support.
Turn off SPF for your domain
To turn off SPF for your domain, delete the DNS TXT record for SPF at your domain provider. Use the steps in Help prevent spoofing and spam with SPF as a guide.
For help with turning off SPF for your domain, contact your domain provider. Google doesn't support issues with your domain host.