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Getting started with email | BT Business
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Getting started with email

Primary and secondary users

Here in BT Business we have what we call 'primary' and 'secondary' users of our system.

The primary user is, as you might have guessed, in overall control: the primary user can do more things than a secondary user, like reset passwords, add new users, and so on. There’s only one primary user.

There can be more than one secondary user. The primary user gives secondary users access to particular parts of the system and lets them do specific tasks only but they can only make changes on their own account.

If you're upgrading and have tasks to complete, you'll need to sign in as the primary user.

To make changes to your account, sign in to My account.

How much mailbox storage space is available?

The amount of mailbox storage space available is dependant on which subscription licence you have.

  • BT Business Email Lite (powered by Microsoft Office 365) licences allow mailbox storage up to a total of 1GB.
  • Office 365 licences allow mailbox storage up to a total of 50GB.

Email size limits

Message Size Limits

Business Email Lite (powered by Microsoft Office 365)

  • The message size limit for Exchange Online POP is 25MB, including attachments. This size limit applies to all messages (inbound, outbound, and internal) and can't be amended.
  • The default attachment size limit for a single attachment is 10MB.
  • Messages larger than 25MB will not be delivered, and the sender will receive a Non- Delivery Report (NDR).
  • Message size limits are necessary to prevent large messages from negatively affecting system performance and to ensure fast message delivery for all users.

Microsoft Office 365


Recipient size limits

These limits apply to emails sent within an organisation as well as to messages delivered to external organisations.

Business Email Lite (powered by Microsoft Office 365)

  • Each Exchange Online mailbox can send messages to a maximum of 10,000 recipients per day.
  • An email message can be addressed to a maximum of 500 recipients.

Microsoft Office 365

  • Each Exchange Online mailbox can send messages to a maximum of 10,000 recipients in any rolling 24-hour timeframe.
  • An email message can be addressed to a maximum of 500 recipients.

    To stop users from sending unsolicited bulk messages, Exchange Online has restrictions that prevent users and applications from sending large volumes of email.

    To send legitimate bulk commercial email (for example, customer newsletters) you should use third-party providers that specialise in these services.


Message Rate Limits

To maintain service and help guard against inappropriate use, users can send only 30 messages per minute.

If you submit messages at a faster rate, Exchange Online will deliver the messages but will queue them at the server and will manage the rate of delivery.


Deleted Item Recovery

When a single item is deleted and then removed from the Deleted Items folder, there is a maximum period of 14 days to be able to recover these items.

Where an entire mailbox is deleted, there is a maximum period of 30 days to be able to recover this.

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