New Outlook cannot add IMAP account – “Changing the ImapRemoteServerInfo is not allowed”

Sercan Egilmezkol 0 Reputation points
2026-08-31T12:15:13.7066667+00:00

We have an IMAP email account: [Moderator note: Personally Identifiable Information removed]@avciss.com.

The account was previously working correctly in New Outlook with the following settings:

IMAP server: avciss.com

IMAP port: 993

IMAP encryption: SSL/TLS

SMTP server: avciss.com

SMTP port: 587

SMTP encryption: None

The mail server configuration was subsequently changed to the following:

IMAP server: mail.avciss.com

IMAP port: 993

IMAP encryption: SSL/TLS

--
SMTP server: mail.avciss.com

SMTP port: 465

SMTP encryption: SSL/TLS

The new settings work correctly in webmail and Classic Outlook.

However, we cannot add this account to New Outlook anymore. We have tried on multiple different PCs and get the same result.

Another IMAP account on the same mail server ([Moderator note: Personally Identifiable Information removed]@avciss.com) can be added to New Outlook successfully using the new server settings. But please keep in mind, this account ([Moderator note: Personally Identifiable Information removed]@avciss.com) was not using New Outlook before. It was used with Outlook Classic.

We investigated the New Outlook request using DevTools. When trying to add the account with the current server settings, Microsoft returns the following response:

"idpStatusCode": "BadRequest",

"error": "BadRequest",

"errorDescription": "Changing the ImapRemoteServerInfo is not allowed. Attempted to changed it from 'avciss.com' to 'mail.avciss.com'"

We also tested the old server name (avciss.com). In that case, authentication fails with:

"idpStatusCode": "Unauthorized",

"error": "InvalidCredentials",

"errorDescription": "Unable to authenticate with credentials provided"

The credentials are valid because the same account works correctly in webmail and Classic Outlook using the current settings.

It appears that New Outlook / Microsoft's Cloud Account service still has an old IMAP server reference (avciss.com) associated with this email account and does not allow it to be changed to the current server (mail.avciss.com).

Could you please advise how we can reset or remove this old IMAP/Cloud Account reference so that the account can be added to New Outlook using the current IMAP server, mail.avciss.com?

Outlook | Windows | New Outlook for Windows | For business
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  1. Helmut Bezolt 0 Reputation points
    2026-09-04T11:31:14.8966667+00:00

    @Alina Le Isn't it the same issue as: https://techcommunity.microsoft.com/discussions/OutlookGeneral/new-outlook-changing-the-imapremoteserverinfo-is-not-allowed-after-host-migratio/4533161

    From what I have read there is that the server caches the old IMAP configuration and doesn't allow a new one.

    I have the same issue on an account.

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  2. Alina Le 4,920 Reputation points Independent Advisor
    2026-08-31T13:23:58.2533333+00:00

    Hello Sercan,

    If I understand correctly, this specific IMAP account previously worked in New Outlook when the mail server was configured as avciss.com. However, after the server was changed to mail.avciss.com, the account can no longer be added to New Outlook. Meanwhile, the same mailbox continues to work correctly in webmail and Outlook Classic, and another IMAP account hosted on the same server can be added successfully using the new server settings.

    "errorDescription": "Changing the ImapRemoteServerInfo is not allowed. Attempted to changed it from 'avciss.com' to 'mail.avciss.com'"

    I would suggest some troubleshooting steps for you to see if it helps:

    1/ Remove the account completely from New Outlook

    Please check whether the mailbox is still listed anywhere in New Outlook.

    Open New Outlook.

    • Select "Settings" in the top-right corner.
    • Select "Accounts".

    Locate the affected mailbox.

    • Choose "Remove".

    If you see the option"Remove from all devices", please select it as well. This option has been suggested in a similar case involving New Outlook retaining previous account configuration information.

    This step helps ensure that New Outlook is not reusing previously stored account settings.

    *Before you begin:

    • Please make sure you know the mailbox password before removing the account.
    • You may be asked to sign in again after the account is removed.

    2/ Add the account using "Advanced Setup"

    Verify whether New Outlook can create a completely new IMAP profile instead of reusing previously stored server details.

    • Open New Outlook.
    • Select "Add Account".
    • Enter the email address.
    • If Outlook starts automatic account detection, select"Cancel" when available.
    • Select "Advanced Setup".
    • Manually enter:
      • IMAP Server: mail.avciss.com
      • IMAP Port: 993
      • Encryption: SSL/TLS
      • SMTP Server: mail.avciss.com
      • SMTP Port: 465
      • Encryption: SSL/TLS

    Reference thread:

    I changed Hosting Provider and associated DNS. New Outlook keeps reconfiguring accounts with previous host's servers

    I hope I've been able to help in some way. Please keep me posted. 

    Kind regards,

     

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