The object <Name of Recipient> has been corrupted or isn’t compatible with Microsoft support requirements, and it’s in an inconsistent state. The following validation errors happened:
There are too many proxy addresses: <X>, and maximum supported number of recipient proxy addresses is 200.
To increase reliability and performance of the service, Microsoft has changed the limit on the number of email addresses that a recipient can have.
- The current new limit is set to a maximum of 200 email addresses per object. This limit is documented in Exchange Online Limits.
- The limit will be increased to 400 by the end of November 2016. Documentation will be updated accordingly.
To reduce the number of email addresses for recipients who exceed the limit, do one of the following:
- In the Exchange admin center, select multiple email addresses, and then remove them from the recipient in a single operation (before you click Save). Saving the changes will work if the resulting number of email addresses for the recipient is less than the current limit.
- If you want to keep the list of email addresses that you're removing from the recipient, follow these steps:
- Export the list of addresses that's currently assigned to the recipient by using a preferred method.
- Use a tool such as Microsoft Excel to determine the list of addresses that you want to remove from the recipient.
- Pass the list to the Set-Mailbox cmdlet as a single operation. If removal is performed as a single operation, and the resulting number of email addresses is under the limit, the update should be successful.