Unable to launch Zoom app from outlook

[MM93]

I have a colleague who when trying to launch a Zoom meeting within Outlook for iOS it leads them to the webpage to join the meeting. Once in the webpage window, it tries to redirects to the app store and reinstall the Zoom App even though it's already installed. It then doesn't join the meeting and you have to enter the session keys manually within in the app. Is there a way round this please?