Outlook says it is sending from my account but it sends it from a psudonomised account

This usually happens when the Microsoft account was set up with a third-party address or when the primary alias is not an Outlook.com or Hotmail.com alias. In that case, Outlook can show and send as outlook_[long series of letters and numbers]@outlook.com, and replies can bounce.

Use one of these supported fixes:

1. Switch the primary alias to an Outlook.com or Hotmail.com address
   • Go to https://account.live.com/names/Manage.
   • Sign in to the Outlook.com account.
   • If there is no Outlook.com or Hotmail.com alias yet, create one by choosing Add email and a new alias and then Create a new email address and add it as an alias.
   • Set the Outlook.com or Hotmail.com address as the primary alias.
   • In Outlook for Windows, remove and re-add the account.
2. If using Outlook for Windows, set the account up manually as IMAP or POP
   • Close Outlook.
   • Press Windows key + R, type outlook /profiles, then select OK. There must be a space between outlook and /profiles.
   • In Choose Profile, select Options > New.
   • Enter a new profile name and select OK.
   • Choose Advanced options > Let me set up my account manually.
   • Enter the password and select Connect.
   • If setup fails, select Change Account Settings and enter the server details from the email provider or the POP/IMAP server reference.
   • In Choose Profile, select Set as default profile and select OK.

If multiple accounts exist in Outlook, the From button can be used to choose which account sends a message, but that only changes the sending account selection. It does not fix the pseudonymized outlook_[...]@outlook.com issue unless the alias/profile problem above is corrected.

• Outlook.com email account appears as "outlook_[long series of letters and numbers]@outlook.com" in Outlook for Windows
• Change the account used to send email messages