問題

The Confluence Data Center and Server mobile app throws the following error when a user tries to connect it to an existing Confluence server site:

診断

• Site URL is accessible by a web browser but not mobile App.
• To test the SSL certificate chain, there are lots of emulators but this one is available SSL Shopper and has lots of tests capabilities.
• Select "SSL checker" button, will redirect to below page to enter server hostname (which must be public) as shown in this image:
  
  

• Enter the server hostname: ex. "myconfluence.com"
• Click on Check SSL
• Then client SSL/TLS transparent session will be established to your remote server speaking SSL/TLS. This test to make sure certificate is correctly installed, valid, trusted and doesn't give any errors to any of your users. a successfull test should be giving the result as shown below
  

• If your certificate is missing an intermediate CA, affecting the certificate chain. you will get the error message as below image:
  
  

ソリューション

• Depending on the error message, you will need to install the correct certificate on your Mobile. In that example, the intermediate certificate is missing and need to be included on Mobile to allow a secure connection.
• You can extract the intermediate certificate from a web browser by using one of those links  How to export SSL certificate using IE Or How to export SSL certificate using Chrome on MacOS
• Then install your certificate on your mobile.
  

  Manually install your certificate on an Android device

  To install a certificate on your Android phone or tablet:

  1. Access the certificate on your device (for example, download it from a location provided by your admin, or open it from an email).
  2. When prompted,   Make sure to select credential use: VPN & apps as for android systems certificates that is used by Apps are different than other system certificate used by browsers, for more details please review this link Developer Android Security Certificate. 
     
     
     
     
  3. Follow the prompts to install the certificate.

  These instructions are for Android 7.0.  Your version, or device's implementation, might differ. See https://support.google.com/nexus/answer/2844832?hl=en for more information.