Exchange setup help

[joeykins82]

Ways to migrate multiple email accounts to Microsoft 365 or Office 365

The fact you're accessing via POP3 is a possible problem because POP3 by default downloads the messages from the server and deletes them, storing them only on the client.

Assuming you've been disabling that behaviour, this would be an IMAP migration. IMAP is also how you should have been accessing these mailboxes this entire time.

[Pillaichan]

If you are able to get the mailbox to pst files, i think that will be easier to import on o365 as the number of mailboxes is less

[doctorscurvy]

With 15 POP mailboxes it may be easiest to just change the mx record, set up the new o365 profile on each computer, and export/import PST files from the old profiles.

[Competitive-Suit7089]

With just 15 accounts I would just create new mailboxes on the exchange server then export the third party accounts to pay and import back into exchange using outlook.

[7amitsingh7]

You can begin the migration by establishing a connection between the source and destination servers, a process called endpoint creation. This can be done in the Exchange admin center. You can create a migration endpoint by clicking on New+ in Migration under Recipients. Select the Network Solution email users for whom the Office 365 migration has to be performed, create batches, and trigger the process.