I am receiving DMARC errors

Hi IBN22​, even without the exact bounce, a sudden "DMARC error" usually means one of these changed overnight:

SPF/DKIM broken or missing
1. Check your DNS has a valid SPF record for your sender, only one SPF TXT, includes the right service
2. Make sure DKIM is enabled in your mail provider and the two DKIM CNAME/TXT records still exist

DMARC policy too strict for your real senders
1. If you recently set p=reject/quarantine, any service sending "as you" but not aligned like website forms, CRM, scanners, so it will fail.
2. Temporarily set DMARC to p=none to stop blocks while you fix alignment.

New/unknown sender started using your domain
1. A new tool like marketing platform, ticketing, etc., may be sending without being added to SPF/DKIM.

To move forward we still need what Zohaib_Yousuf​ asked for: the exact NDR/bounce text, your domain, and one failed message header, that will tell us whether it's SPF fail, DKIM fail, or alignment.

Let us know with those details and we'll pinpoint the fix.