The reason for the bounce backs are due to Google that has upgraded their security, Which would now require your records to be compatible. In this article we will show you how to update the specific record to eliminate this issue
Step 1. Log into Cpanel
Step 2. Click on Zone editor
Step 3. Click on Manage
Step 4. Click on TXT
Step 5. Click on Edit
Step 6. You can then add the standard SPF record and click save after
NOTE: If an SPF record already exist you can replace it with the record below
v=spf1 a mx include:relay.mailchannels.net ~all