Hi Craig Payne,
Welcome to the Microsoft Q&A forum.
From your description, it sounds like the email account may have been compromised. I understand how stressful it is to have the Outlook app stop connecting while suspicious messages keep reappearing.
The Q&A Assist answer under your thread is generally on the right track. Please try its key checks first (account security, reviewing Rules and Forwarding in Outlook on the web, and using “Sign out everywhere”), and note what changes after each step. The “Sign out everywhere” action can take up to 24 hours to fully apply across services.
To add a bit more helpful context (especially for the iPhone app connection issue and the message reappearing):
1, iPhone Outlook app still not connecting
If the Outlook app on iOS still will not connect after the account is secured and you have signed out everywhere, try resetting the device sync connection by removing the device from the Mobile devices list in Outlook on the web, then add the account back to the Outlook app. Microsoft documents that removing the device from the Mobile devices list can help fix sync issues when a device is not sending or receiving mail.
2, Suspicious message keeps reappearing
If you continue seeing mailbox changes after securing the account, re-check Rules and Forwarding again after the sign-out everywhere has fully applied. These settings can remain in place after an account compromise until they are removed. Rules are managed under Settings Mail Rules, and forwarding is under Settings Mail Forwarding in Outlook on the web.
3, Contact support via Outlook.com and via web
If you still need direct help after the steps above, you can use the official Outlook.com support path: in Outlook.com, open Help, search your issue, then scroll to “Still need help?” and choose Yes (sign-in required).
If that in-app Help flow does not help you reach support, try contacting Microsoft Live Chat Support via the web:
- Visit the Microsoft Support contact page: Contact - Microsoft Support
- In the search bar provided on the page, type "Outlook issue" and press Enter.
- Click on the "Get Help" button that appears.
- Scroll down the page until you see and click on the "Contact Support" option.
- When prompted to select your product or service, choose "Other Products".
- For the category, choose "Outlook".
- Look for and click on "Chat with a support agent in your web browser".
- Confirm your personal email when prompted - this is the email Microsoft will use to communicate with you during and after the support session.
- Explain your situation clearly: Be concise but provide all the relevant details.
One detail that would help narrow the next step: can the account sign in successfully on Outlook.com in a web browser, or is the sign-in also blocked there?
I hope this clarifies things.