Email bounces back. He is unable to receive my calendar invites in outlook.

[Abdul Qaderi]

Here is the error code that I got from the exchange online,

Reason: [{LED=554 5.2.0 STOREDRV.Deliver.Exception:QuotaExceededException.MapiExceptionShutoffQuotaExceeded; Failed to process message due to a permanent exception with message Move/Copy messages failed. 16.55847:A5000000, 17.43559:00000000AD010000000000000000000000000000, 20.52176:140F97810500101068010000, 20.50032:140F978175

 

[#2]

Looks like the recipient mailbox has reached its quota?

[#3]

Is the mailbox on litigation hold? Also, try to clean both the 1st level and 2nd level Recycle Bins.

[#4]

The quota is fine I just checked the mailbox properties on O365.