How to delete all emails ending .firebaseapp.com

Outlook.com and Outlook on the web do not support sending messages directly to Deleted Items based only on a domain such as .firebaseapp.com. Junk handling is designed around Junk Email (spam) filtering plus Safe/Blocked lists, not direct auto‑deletion.

What can be done with the available options:

1. Use junk filtering and Blocked senders/domains
   • Go to Settings > Mail > Junk email.
   • Under Blocked senders and domains, add the specific sender addresses or domains that are sending the unwanted mail.
   • Messages from those senders/domains will be treated as junk and moved to the Junk Email folder rather than Inbox.
2. Use Safe senders to protect legitimate mail
   • In the same Junk email settings page, use Safe senders and domains to ensure important senders are not treated as junk.
3. Clean up Junk and Deleted Items
   • Items moved to Junk Email can be removed in bulk by opening the Junk Email folder and using Delete all.
   • When items are deleted from any folder, they go to Deleted Items first. To permanently remove them:
     • Open Deleted Items and use Empty folder to delete everything, or
     • Select specific items and delete them.
4. Storage and permanent deletion
   • Messages in Deleted Items still count toward mailbox storage until the folder is emptied.
   • To permanently delete without using the Deleted Items folder, select messages and press Shift+Del.

Outlook’s built‑in model is therefore: filter to Junk Email using junk settings and blocked domains, then periodically empty Junk Email and Deleted Items, rather than auto‑routing directly to Deleted Items based on domain.

References:

• Filter junk email and spam in Outlook
• Options > Junk Email
• Mailbox storage limits in Outlook
• Read and send email in the light version of Outlook
• Delete all email in Outlook on the web