Office 365 Mail sending problem with Thunderbird

Problem: SMTP settings of office365 don’t work with Thunderbird. POP and SMTP work so you can receive emails but sending doesn’t work.
Resolution: You need to disable the smtpautorization.

First Install the exchange online management module in an elevated power shell running this command

Install-Module -Name ExchangeOnlineManagement -RequiredVersion 2.0.5

Then import the module

Import-Module ExchangeOnlineManagement

Now you can connect with your account online , you need to be the admin user. You will be prompted to enter your login credentials after running this.

Connect-ExchangeOnline -UserPrincipalName youradminemail@domain.com

Now you can modify your user account by running

Set-CASMailbox -Identity useremailaccount@domain.com -SmtpClientAuthenticationDisabled $false

You can see if it worked by running this. You will see a table with all the paramenters and SmtpClientAuthenticalionDisabled should be set to $false

 Get-CASMailbox useremailaccount@domain.com

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