Note : Perform the below steps on Secure Mail and Secure Web.
Step 1 : Go to Citrix Endpoint Management console> Configure> Applications.
Step 2 : Select Secure Mail and Edit

Step 3 : Enter application's Application identifier in "Restricted Open-In exception list" and app schema under "Allowed URLs".
See below instructions for commonly used meeting applications
Microsoft Teams:For iOS: In Restricted Open-In exception list, add : com.microsoft.skype.teams
In Allowed URLs, add: +^msteams:
Zoom:For iOS: In Restricted Open-In exception list, add : us.zoom.videomeetings
In Allowed URLs, add: +^zoomus:
GOTOMeeting:For iOS: In Restricted Open-In exception list, add : com.logmein.gotomeeting
In Allowed URLs, add: +^LMI-G2M://
Webex:For iOS: In Restricted Open-In exception list, add : com.webex.meeting
In Allowed URLs, add: +^webexteams:
Google Meet:For iOS: In Restricted Open-In exception list, add : com.google.meetings
In Allowed URLs, add:
Problem Cause
Application Identifiers were missing from "Restricted Open-In exception list" and "Allowed URL's"