MX Verification is not working after Domain expired and re-enabled.

MX Verification is not working after Domain expired and re-enabled.

Hi,
We had the domain expire on August 2nd and we re-established it but the MX verification is not working and so the relay is failing and giving back 553 errors when trying to send emails.
We have the correct MX records set up because we are still receiving emails but Zoho won't let us send new ones.

Please advise.
Facundo