Select your language

Hosted Exchange: How can I use my subscription alongside Microsoft 365?

Note: This help article applies only to Hosted Exchange. If you are not sure which email service you use, you can find more information in the following article.

https://www.green.ch/en/which-email-service-do-i-use

 

Hosted Exchange can generally be used together with certain Microsoft 365 services. Whether they can be used in parallel depends on which Microsoft 365 licence is used and whether it includes its own Exchange service.

Microsoft 365 licences with Exchange Online and Hosted Exchange both provide email services for the same domain. This may result in conflicts with email delivery, Autodiscover, Outlook configurations, DNS records and user management.

 

When is parallel use possible?

Parallel use is generally possible if the Microsoft 365 licence being used does not include its own Exchange service.

Microsoft 365 Apps for Business, for example, can be used together with Hosted Exchange because this licence does not include an Exchange service.

In this case, the following Microsoft services can be used while emails continue to be handled through Hosted Exchange:

  • Microsoft Office applications
  • OneDrive
  • Microsoft 365 web applications without their own Exchange service

 

When is parallel use not possible?

Microsoft 365 licences that include Exchange Online should not be used in parallel with Hosted Exchange on the same domain.

In this case, two different Exchange systems would be used for the same domain. This may lead to technical conflicts.

Possible effects:

  • Email delivery problems
  • Errors with Autodiscover and Outlook configurations
  • Unclear assignment of responsibility for mailboxes
  • Conflicts with DNS records
  • Problems managing users and email services

 

Hosted Exchange and Microsoft Teams

If Microsoft Teams is to be used with a Microsoft 365 licence that also includes Exchange Online, a migration from Hosted Exchange to Microsoft 365 is generally required.

In this case, the mailboxes should be moved completely to Microsoft 365 so that all services are operated within the same Microsoft 365 environment.

 

Migration from Hosted Exchange to Microsoft 365

If parallel use is not possible or all Microsoft 365 services are to be used, a complete migration of the mailboxes to Microsoft 365 is recommended.

Before a migration, check the following points in particular:

  • Existing Hosted Exchange users
  • Email addresses and aliases
  • Calendars and contacts
  • Forwarding
  • Distribution groups
  • Shared mailboxes
  • Resource mailboxes
  • DNS configuration of the domain
  • Required Microsoft 365 licences

Back up all required data before making the change.

Do not remove or cancel Hosted Exchange until:

  • All data has been migrated successfully
  • The mailboxes have been checked
  • The email flow has been tested successfully
  • Calendars, contacts and other functions are working correctly

You can find further information about backing up and transferring data in the following articles:

https://www.green.ch/en/outlook-windows-mailbox-import/export

https://www.green.ch/en/outlook-macos-mailbox-import-/-export

https://www.green.ch/en/apple-mail-mailbox-import/export

https://www.green.ch/en/thunderbird-windows-mailbox-import/export

https://www.green.ch/en/imap-data-transfer

 

In some migrations, former Hosted Exchange domains may still be treated internally as local Exchange domains. This may result in delivery problems or routing conflicts.

 

Note: If delivery problems continue after a migration or emails are not delivered correctly to external recipients, technical follow-up work on the former Hosted Exchange domain may be required. In this case, contact support.

You can find further information about the migration in the following article:

https://www.green.ch/en/migration-from-hosted-exchange-to-microsoft-m365

 

Hosted Exchange and Outlook

Outlook can be used with both Hosted Exchange and Microsoft 365. The decisive factor is which Exchange service is being used in the background.

If the same domain is used simultaneously in Hosted Exchange and Exchange Online, Autodiscover conflicts may occur. This may cause Outlook to attempt to connect the mailbox to the wrong Exchange system.

Possible consequences:

  • Repeated password prompts
  • Failed account setups
  • Connection to the wrong Exchange service
  • Incorrect Autodiscover results

You can find further information in the following article:

https://www.green.ch/en/hex-outlook-autodiscover-issue

 

Check before making a change

Before a new installation or migration, always check first which Microsoft 365 licence is being used and which services it includes.

The included services determine whether Hosted Exchange can be used in parallel or whether a complete migration to Microsoft 365 is required.

Check in particular whether the licence includes Exchange Online.

Note: If it is unclear whether your Microsoft 365 licence includes an Exchange service or whether the desired combination is supported, contact support before setup.

 

Further information

Hosted Exchange overview:

https://www.green.ch/en/all-about-hosted-exchange

Migration to Microsoft 365:

https://www.green.ch/en/migration-from-hosted-exchange-to-microsoft-m365

Cancel Hosted Exchange:

https://www.green.ch/en/cancel-hosted-exchange-2016

Hosted Exchange connection details:

https://www.green.ch/en/email-connection-details-hosted-exchange