One of my client was having issues with emails. I have search a lot to fix the issue. I have checked and found all the DNS entries were correct, but still it was giving error message for SPF.
After digging a lot regarding the issue, I found that there is record in whm which is Enable Sender Rewriting Scheme (SRS) Support which is disabled by default. I have made it enable and issue was fixed. Please carry out following steps to fix this issue.
Login to WHM
There in search bar type in Exim Configuration Manager
Go to Basic Editor>> search for Enable Sender Rewriting Scheme (SRS) Support And make it ON
Your issue is fixed.