Nexus365 delegated mailboxes

Guidance for people with delegated access to other mailboxes

This guidance relates to mailboxes that have been automatically mapped to your profile, rather than ones you have manually added.

Email accounts are being moved to the cloud-based Nexus365 service in batches according to their primary affiliation (as indicated in the ‘company’ section of the global address list that appears when you click on ’To’ in a new email).  The migration to Nexus365 starts in February 2018 with the pilot, while the majority of email accounts are being migrated between April and July.  During this period we will be in a hybrid state when some email accounts are on the Nexus365 cloud-based service while others remain on the existing service.

A mailbox to which you have delegated access could be moved to Nexus365 ahead of your own email account because the two accounts have different primary affiliations, maybe due to you working on a project for a different unit.  If this happens you will experience some issues using and accessing the other mailbox until your own account has been migrated to Nexus365.

You might receive pop-up messages and the mailbox will disappear from your email account. Your permissions for this mailbox will remain in place but you will no longer have visibility of it. The following guidance shows what you need to do to address this issue while we are in the hybrid state:

A. If you see this Microsoft Exchange pop up box:


  1. Click OK
  2. Restart Outlook

Depending on how your account is set up this may be all you need to do.

B. If you see this Microsoft Outlook log-in prompt:

outlook box screenshot









When logging in for the first time, or after the Microsoft Exchange pop-up box above:

  1. You must ensure that your username is followed by
  2. If you have to add, remember to tick Remember my credentials.
  3. Your password is unchanged so remains as it was before.

C. If a mailbox has disappeared from Outlook (e.g. a team mailbox or one to which you have been delegated access by the owner):

Please consider if you need access to the mailbox immediately:   

IF NO: You do not need to do anything further – the mailbox will be visible again when your account is moved to Nexus365.

YES: You will need to manually add the mailbox (see below).  You will then need to remove it after your account has been migrated, to avoid it appearing twice in your account.

To add a mailbox:
  1. Within Outlook, click on the File menu and then on the Account Settings button.
  2. Select Account Settings from the drop down list.
  3. Select the Email tab, click your account in the list, click Change and then click More Settings.
  4. On the Advanced tab, under Open these additional mailboxes, click Add and enter the mailbox name that you wish to add to your profile.
To remove the mailbox once your account has moved to Nexus365:
  1. Within Outlook, click on the File menu and the on the Account Settings button.
  2. Select Account Settings from the drop down list.
  3. Highlight the additional mailbox and click x Remove.
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