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1) enable exchange via SMTP and POP3 (or IMAP) protocols (POP protocol is used less and less often as it is insecure and many mail servers do not recommend it, IMAP is preferable).
2) Enable two-factor authorization in your Google account settings;
3) then go to the link https://myaccount.google.com/apppasswords and generate a password for 1C:FirstBit application - the password will be shown to you only once, it should be memorized (copied and saved) and then used when setting up email account in 1C system.
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II. If you need to add a Yandex-mail account (relevant for Russian clients), the configuration will be done as follows:
1) enable exchange via SMTP, POP, IMAP
2) enable application password settings on your account on Yandex and generate an additional password, which should be specified in the settings in the application for exchange (for example, on your phone or in the 1c program) - it is not the same password with which we usually enter the mail in the browser).
III. Use generated password in this field