Xero.com provide a feature which requires the use of an ! in the email address

Paul
1
Reputation point
Unfortunately, this causes the following NDR when sending an email to it:
Server error: '550 Mailcore(2503): Restricted characters in address'
An example of the email address format is such:
'bills.!dbfjz.x4ye0qqkh4rk9izm@xerofiles.com'
I read that an exclamation mark is a valid character in the local part of an email address, but Office 365 doesnt seem to like it.
Is there any way around this? I can Admin my tenancy if required, although I havent got a clue how to do it as I set it up years ago LOL
Thanks
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