Error message when initiating an "" pop/smtp mail

The error message is:
[AirSync] Creating or updating folder ‘/Inbox’ failed due to the following error: AlreadyExists

Also, the send button doesn’t wok with this particular account, while there are no similar issues with other gmail and own domain mail accounts configured on eM Client. The composed message is placed in “Outbox” and is sent only when starting send/receive process.

You can’t use POP3 with

Go to Menu > Accounts and click on Add Account. Enter the email address in the automatic setup. Once the account is setup, move all the messages from the old POP3 folders to the new ones, then remove the POP3 account from eM Client.

See if you still get any errors.

It is possible for POP3 in Outlook Microsoft can tell how to do at this:

Torsten Marx

No, it is no longer possible to use POP3 because Microsoft require Modern Authentication / oAuth which is not possible with manual setups in eM Client. If you setup the account manually as POP3, which is the only way you can setup as POP3, it will use a username/password login which is no longer supported by Microsoft servers. In order to use oAuth the account needs to be setup using the automatic setup in eM Client, which will use IMAP instead.

See here: Microsoft disables Basic authentication for all accounts | eM Client

It must be a issue for eM Client as I have in Thunderbird and Mail works finely

Torsten Marx


Es fällt mir nicht leicht, meine Gedanken auf Englisch auszudrücken, daher ist es möglich, dass ich mich nicht sehr gut ausgedrückt habe, um Ihre Zustimmung zu erhalten.
Ich habe nicht gesagt, dass ich den eM Client für minderwertig, besser oder schlechter als Thonderbird halte. Es ist nicht meine Aufgabe, einen Vergleich anzustellen, der sowieso subjektiv wäre. Ich habe lediglich zum Ausdruck gebracht, was ich für eine Tatsache halte: Es ist Sache des Einzelnen, eine persönliche Entscheidung zu treffen.

Torsten Marx


It must be a issue for eM Client as I have in Thunderbird and Mail works finely.

If you are still using with a POP account setup in Thunderbird using the old basic username and password login, then its a glitch in the Microsoft system as that was disabled by Microsoft as @Gary advised starting from Oct 2022 and completely disabled as of early 2023.

So you now have to login via OAuth 2.0 token to access your account which only works in eM Client via the automatic email wizard using an IMAP setup as @Gary advised above.

Extract below from the Microsoft page about the authentication changes for Mail clients that now require users to change to modern OAuth 2.0.

“What we are changing”

We’re removing the ability to use Basic authentication in Exchange Online for Exchange ActiveSync (EAS), POP, IMAP, Remote PowerShell, Exchange Web Services (EWS), Offline Address Book (OAB), Autodiscover, Outlook for Windows, and Outlook for Mac.

We’re also disabling SMTP AUTH in all tenants in which it’s not being used.

This decision requires customers to move from apps that use basic authentication to apps that use Modern authentication. Modern authentication (OAuth 2.0 token-based authorization) has many benefits and improvements that help mitigate the issues in basic authentication.

This can not be generalized without knowing whether @k.aly uses Exchange Online or by he means a free live/hotmail/ account.
In the case of the latter, basic authentication still works and IMHO there is no deadline for deactivating it known yet.


Neither of these accept basic authentication.

Please see: