Dear Costar
Thank you for your attention and response!
In order to assist you better, we need more information from you so that we can better judge and analyse the problem for you.
Could you please let me know your Loop version number? After our testing, it is opened properly. Our version number is: Version 2.84 (24040916). You can click on the Settings icon in the bottom left corner once you are in Loop and it will show you your version number. And check if the problem exists after updating your Loop!
From which source did you download the Loop? You can refer to the download method in this link to download, please refer to: Install the Loop iOS app - Microsoft Support

To rule out a problem with your mobile, you can try to check if the problem still exists on other mobile devices.
Thank you again for your support and understanding as well as your trust and patience!
Best Regards,
Maxine | Microsoft Community Support Specialist