Apple Mail stopped receiving e-mails and says "could not connect to this Exchange server"

Question

Apple Mail stopped receiving e-mails and says "could not connect to this Exchange server"

Leros Magazine 20

I pay to use Microsoft Exchange and have been using it with Apple Mail on my MacBook since 2022. Today I stopped receiving e-mails and my inbox was empty. I removed Microsoft Exchange and when I try to configure it manually it says "unable to verify account name or password".
If I try to sign in using the Authenticator, after I enter the 2-digit security code and click "yes" on my iPhone a window appears on my computer screen and says "The operation couldn't be completed. (com.apple.account error 1.).
I have already contacted Apple Care and I was told the problem is on the Microsoft side. I am a business user and need to fix it ASAP. Please help!

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Answer accepted by question author

BabybooHN 3,040 Independent Advisor

Dear @Leros Magazine

I understand how critical it is to get your business email back up and running immediately.

The com.apple.account error 1 and the failed manual Exchange configuration usually point to an authentication handoff issue between Apple Mail and Microsoft Entra ID (Azure AD), often triggered by recent changes in Conditional Access policies, Modern Authentication tokens, or legacy protocol settings.

Here are the step-by-step solutions to resolve this issue:
Step 1: Force Apple Mail to Re-authenticate

Quit Apple Mail completely (Cmd + Q).
Open System Settings > Internet Accounts.
Select your Microsoft Exchange account (or click Add Account > Microsoft Exchange if previously removed).
Do not choose manual configuration. Click Sign In to open the browser-based modern authentication window.
When prompted with Microsoft Authenticator, complete the request on your phone. If the error occurs again, clear your Mac's default browser cache/cookies (or temporarily set Safari as your default browser) and retry.

Step 2: Remove Stale Passwords from macOS Keychain
Cached or corrupted credentials in macOS can block new authentication tokens:

Open Keychain Access on your Mac (Cmd + Space and search for Keychain Access).
In the top-right search box, type Exchange and Microsoft.
Locate and delete any entries related to your Microsoft 365 / Exchange account (e.g., com.apple.account... or adal...).
Restart your Mac, then go back to System Settings > Internet Accounts and re-add the Exchange account.

Step 3: Verify Admin Settings (Microsoft 365 Admin Center)
If you are the tenant administrator (or have access to the admin portal):

Go to the Microsoft 365 Admin Center.
Go to Users > Active Users and select your account.
Under the Mail tab, click Manage email apps.
Ensure Authenticated SMTP and Exchange Online PowerShell / EWS permissions are enabled.
Check if any strict Conditional Access policies (such as requiring compliant devices or specific app protections) were recently updated in the Entra Admin Center.

For official details regarding Apple Mail authentication and setup with Exchange, you can refer to the Microsoft Official Documentation on Setting up Exchange on iOS/macOS.

Please try these steps and let me know if you encounter any specific error during Step 1 or Step 2. I am here to help you get this resolved.

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Leros Magazine 20 Reputation points

2026-09-04T22:01:44.59+00:00

I opened Keychain Access and deleted most entries related to your Microsoft 365 / ExchangeI but could not remove Microsoft ECC Root Certificate Authority 2017 and Microsoft RSA Root Certificate Authority 2017 from Keychain Access. When I tried to delete them a window appear on my MacBook screen saying "An error occurred while deleting “Microsoft RSA Root Certificate Authority 2017 / UNIX[Read-only file system]".
When I go to the Microsoft 365 Admin Center and clicked the mail tab I cannot find "Manage email apps" because under this tab there is only one line saying "We are preparing a mailbox for the user."
Please help.
BabybooHN 3,040 Reputation points Independent Advisor

2026-09-06T16:40:15.85+00:00
Dear @Leros Magazine

Thank you for providing those details! Here is what is happening and how to address each issue:
Step 1: Regarding the Root Certificates error (UNIX[Read-only file system])

You do not need to delete these certificates, and it is completely safe to leave them as they are.

System Root Certificates (like Microsoft ECC/RSA Root Certificate Authority 2017) are stored in macOS system directories protected by System Integrity Protection (SIP), making them read-only.

Impact: These are valid root authority certificates required by macOS for standard SSL/TLS encryption verification. They are not cached user credentials and will not cause the Apple Mail authentication error. As long as you deleted the cached credential entries (such as com.apple.account..., adal..., or specific Exchange password entries under login keychain), you have completed the necessary credential cleanup.

Step 2: Regarding "We are preparing a mailbox for the user"
This status indicates why Apple Mail stopped working: Exchange Online has not finished provisioning the mailbox or its license assignment/provisioning is incomplete/stuck.

To resolve this:

Check License Assignment:

In the Microsoft 365 Admin Center, go to Users > Active Users and click your account.

Go to the Licenses and apps tab.

Verify that an active license containing Exchange Online (e.g., Microsoft 365 Business Basic/ Standard or Exchange Online Plan 1/2) is assigned.

Toggle the license OFF, save changes, wait 1–2 minutes, then toggle it back ON and save.

Allow Provisioning Time / Check Service Status:

If the account or license was recently created or modified, mailbox provisioning can take anywhere from a few minutes up to 24 hours to complete.

Check Health > Service health in the Admin Center to ensure there are no ongoing Exchange Online outages affecting mailbox provisioning in your region.

Verify Outlook on the Web (OWA) Access:

Try logging directly into Outlook on the web

If OWA loads your inbox: The mailbox is ready. Return to macOS System Settings > Internet Accounts, re-add the Exchange account using the automatic Sign In prompt (not manual setup), and Apple Mail should sync smoothly.

If OWA shows an error (e.g., "Mailbox Not Found" or "Setting up..."): The mailbox is stuck provisioning. You may need to contact Microsoft 365 Support via the Admin Center (under Support > Help & support) to run a backend mailbox diagnostic.

Please let me know how it goes after checking the license status and trying OWA.
Leros Magazine 20 Reputation points

2026-09-07T12:41:53.9533333+00:00

After toggling the license off and back on I succeeded in re-adding the Exchange account and can now receive e-mails on my MacBook Pro using Apple Mail. Thank you for your assistance.
BabybooHN 3,040 Reputation points Independent Advisor

2026-09-07T17:51:33.09+00:00

Dear @Leros Magazine

Thank you for patiently trying these steps. If you have any further questions, please let me know, and I will be happy to assist you.

1 additional answer

Your answer

Leros Magazine 20 Reputation points

2026-09-04T22:01:44.59+00:00

I opened Keychain Access and deleted most entries related to your Microsoft 365 / ExchangeI but could not remove Microsoft ECC Root Certificate Authority 2017 and Microsoft RSA Root Certificate Authority 2017 from Keychain Access. When I tried to delete them a window appear on my MacBook screen saying "An error occurred while deleting “Microsoft RSA Root Certificate Authority 2017 / UNIX[Read-only file system]".
When I go to the Microsoft 365 Admin Center and clicked the mail tab I cannot find "Manage email apps" because under this tab there is only one line saying "We are preparing a mailbox for the user."
Please help.
Leros Magazine 20 Reputation points

2026-09-07T12:41:53.9533333+00:00

After toggling the license off and back on I succeeded in re-adding the Exchange account and can now receive e-mails on my MacBook Pro using Apple Mail. Thank you for your assistance.
BabybooHN 3,040 Reputation points Independent Advisor

2026-09-07T17:51:33.09+00:00

Dear @Leros Magazine

Thank you for patiently trying these steps. If you have any further questions, please let me know, and I will be happy to assist you.

Answer 1

Leros Magazine 20

Accepted. After struggling I followed your step by step instructions and got my e-mails back

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