This article guides you through the steps to fix issue while adding MX entry.
There are two reasons, if even after successful addition of MX entry in your domain, our system is showing error for that upon check.
First, it can be because of DNS propagation. Every server maintains its own DNS catch for a certain period of time.
So, even if mxtoolbox or dns checker is stating dns has propagated, please give it 15 minutes to 2 hours for propagation to finish. As some servers might have old data cached.
Only around 5% of the domains take more than 2 hours for dns to propagate.
Second reason is you are having multiple MX records on your domain. If this is the case, please ensure Mutant Mail's MX records have highest and second highest priority.
Highest priority in MX records mean, the smallest numerical value in priority column. Some DNS/Domain panel accept numerical value 0 as smallest number, while others as 5.
If your existing MX records are having the smallest number, please increase their priority number to higher numerical value. So that, Mutant Mail can take over.