[exim] failed key import from office365

Hi,
I have problem with duplicate emails from office 365, when domain of sender
isn't properly configured.
When sender has some problem with DKIM or SPF record i have warning in exim
"PDKIM: d=[domain].onmicrosoft.com s=selector1-[domain]-onmicrosoft-com
[failed key import].
I have control = dkim_disable_verify
Email is delivered to reciver, but microsoft's smtp servers send this email
next time, every 15 minutes (always from different smpt ip address).

Of course, everything is ok, when domain is correct. Both with DKIN
configured or without but with good SPF record.

Does anyone have any idea how to solve this problem, because many companies
are switching to 365 and making mistakes in dns configuration?

Regards, Edytka.