PowerShell - Connecting to ExchangeOnline - Can no longer add/enable Remote Routing

I have scoped down you answer and make it clearly for you question :

-> Do You Need DisplayName or Password?

No — not in the second CSV that’s only used by PowerShell to add aliases.

You only needed DisplayName and Password in the first CSV when uploading to the Admin Center (which handles creating the users and assigning passwords).

Once the users are created, you only need the fields relevant for the script — so your second CSV can be trimmed to just:

UserPrincipalName,Email1,Email2

@mydomain.org,@mydomain.mail.onmicrosoft.com,*****@mydomain.onmicrosoft.com*

@mydomain.org,@mydomain.mail.onmicrosoft.com,*****@mydomain.onmicrosoft.com*

...

-> Is the script correct? And how does the data fit?

Yes, this script is correct:

Import-Csv "alias-list.csv" | ForEach-Object {

    $UPN = $_.UserPrincipalName

    $Email1 = $_.Email1

    $Email2 = $_.Email2

    Set-Mailbox -Identity $UPN -EmailAddresses @{add=$Email1}

    Set-Mailbox -Identity $UPN -EmailAddresses @{add=$Email2}

}

-> And What goes in the CSV?

As your note:

• Yes, each Email1 and Email2 value should be the full address (e.g., ******@mydomain.mail.onmicrosoft.com).
• There’s no need to include a display name in this second CSV.
• Each row is one user; just make sure the values are accurate.

-> So your Workflow it should looks like this steps:

Step 1 — Create users in M365 Admin Center:

• Download and populate Microsoft’s sample CSV with fields like DisplayName, Username, and Password.
• Upload that CSV in Admin Center > Users > Add Multiple.

Step 2 — Prepare second CSV (for PowerShell):

• Create a simple alias-list.csv like this:

UserPrincipalName,Email1,Email2

@mydomain.org,@mydomain.mail.onmicrosoft.com,*****@mydomain.onmicrosoft.com*

@mydomain.org,@mydomain.mail.onmicrosoft.com,*****@mydomain.onmicrosoft.com*

...

Step 3 — Run the PowerShell script:

Open PowerShell as admin, connect to Exchange Online:

Connect-ExchangeOnline

Then run the alias update:

Import-Csv "alias-list.csv" | ForEach-Object {

    $UPN = $_.UserPrincipalName

    $Email1 = $_.Email1

    $Email2 = $_.Email2

    Set-Mailbox -Identity $UPN -EmailAddresses @{add=$Email1}

    Set-Mailbox -Identity $UPN -EmailAddresses @{add=$Email2}

}

-> This will add the two aliases for each user automatically

You don’t need to set @mydomain.mail.onmicrosoft.com as a secondary alias (Exchange Online routes via UPN by default), but it's good practice for hybrid-like consistency.

• You can confirm aliases with:

*Get-Mailbox *****@mydomain.org | Select-Object -ExpandProperty EmailAddresses

• If aliases already exist, Set-Mailbox won’t overwrite — it just appends.

I hope this information will help you

OMGOSH you are A STAR! Yup, did all that, and imported all my users into O365 which didnt give me a single screw up, then created a CSV file using the fields you said, adding both the "new" alias's, and it worked! That is AMAZING...... WOW, very, very HAPPY! :)

Now I have to figure out how to bulk reset passwords to what I want instead of what MS assigns... we have younger people who will never (heck I wouldn't be able to) remember the password... 16 characters of everything.....

Two things I know, because they are now cloud only accounts, I cant use the set-adaccountpassword command i used before. Also, another old script I had wont work because I cant use the Set-MsolUserPassword command anymore. Maybe Update-MgUser No idea why MS removes command, changes commands. I get it if its a vulnerability, but seems its change for changes sake, and thats never good. <sigh... But even if I havr o change them one by one, its still a LOT better than having to create all those accounts one by one... what would have been a HUGE pain in the bum!

I cant thank you enough, and I know it took time out of your day/night to write all that, so please know I appreciate you, and its great to know there are still good guys (and gals) in the world, who would take time out of their life to help a stranger. You are a good human being.

Thank you for being you, and never let the world change or diminish the good in you. I appreciate you SO very much for all your help, being patient and spelling out what I needed to do. Means a lot. My best, and sincerely, JH

I'm so happy to hear that from you, but to let the other come and make sure my comment is always on top with them. You can make a move to it that will keep my instruction always on top for the other who is lack out of ideas and find to here but with your verification about my comments, that will help them less painful alot. Also that will support me alot to do this more regularly btw ;)

Well I can verify that your instructions worked, are very clear, easy to understand and VERY much appreciated. Anything I can do to make this post of more value to you, you only have to ask. Thanks again for being one of the good ones! Best, JH