Hello,
Thank you for reaching out to the Microsoft Community and I'll be glad to assist you today.
Yes, it appears to be an issue with the Outlook web page on iOS and in Android platforms. However, devices running iOS 18 are able to access Outlook using the Safari browser, and the issue seems to occur mainly when using Chrome on iOS.
If you're facing the same problem even in Safari on iOS, try clearing your Safari browser's history, cache, and cookies. OR
As a workaround, you can sign in with your Microsoft account on https://onedrive.live.com/ or https://www.office.com/ in your Safari web browser on your iPhone.
Then, select the All apps icon in the top left corner and choose the Outlook app.
The Outlook app will automatically sign you in through your Safari web browser, allowing you to access and view all your emails.
Once signed in to Outlook, select the three horizontal lines in the top-left corner, then choose the option to submit your feedback. The developers might address the issue soon.
Recent discussion thread for your reference:
https://answers.microsoft.com/thread/a0df4cd5-8...
Let me know if you still need more help.