If the APNS push is not working, ask the following questions:

• Are port 2195 and outbound port 2196 open from the company network to reach the APNs?
• Is the APNs certificate valid?
• Are the APNs and App Store IP addresses are not present (hardcoded) in the host entry of the XenMobile?
• If there is a proxy for APNs communication, is the proxy working properly?.
• Have you run connectivity checks? For details, see Connectivity Checks. 
• On NetScaler, are the following configurations for the MDM load balancing virtual server set?
• Specific to PORT 443:
  • Enable Session Reuse should be turned ON.
  • SSL Redirect Port Rewrite should be ON.
  • Persistent Timeout should be set to 1440.
• Specific to PORT 8443:
  • Enable Ephemeral RSA should be OFF.

Additional Resources:

Full XenMobile Deployment Handbook

Other Troubleshooting Checklist Articles:

• Troubleshooting Checklist: Users cannot browse internal websites in Secure Web
• Troubleshooting Checklist: Exchange SSO is not working in Secure Notes for iOS, but does work in Secure Notes for Android.
• Troubleshooting Checklist: Users cannot send notes created using Secure Notes via Secure Mail
• Troubleshooting Checklist: In the ShareFile app, Secure Mail, or Secure Notes, the following error appears: "Your connection is unavailable. Only offline files can be accessed."
• Troubleshooting Checklist: In Secure Mail, a "Cannot authenticate to the server <FQDN> because the certificate is not valid” error appears.
• Troubleshooting Checklist: In Secure Mail, an “Access to your company network is not available” error appears.
• Troubleshooting Checklist: In Secure Mail, a “Verify your Single Sign-On credentials” error appears
• Troubleshooting Checklist: Cannot send emails using Secure Mail
• Troubleshooting Checklist: Emails are not syncing in Secure Mail, or email folders are not found, or Secure Mail is prompting users for a password multiple times
• Troubleshooting Checklist: Users cannot access apps in Secure Hub
• Troubleshooting Checklist: Cannot enroll and authenticate a device using Secure Hub