Outlook Folders on iPhone App

For some reason I have one specific folder that does not show up on the app on my iPhone. I can see it on my laptop and desktop but not on my phone. If I use safari on my phone and log in to Outlook online I can see the folder just not on the app. I've tried searching for emails that are located in that folder and the app cannot located any of these emails. I've tried deleting the app and redownloading and resigning in to the app and still no luck. Anyone have any suggestions? Thank you