Problem: I encountered error message “Couldn’t open connection to server” when trying to configure Android mobile.
Made changes in AD security, then configure mobile.
1) Go to Active Directory Users and Computers
2) Click on View, check Advanced Features
3) Right click on user account and selects Properties
4) Click on Security tab and Advanced button
5) Check the box for “Allow inheritable permissions from the parent to propagate to his object and all child objects. Include these with entries explicitly defined here.”
1) Go to Settings
2) click on Add account under Accounts column
3) Select Email and then Microsoft Exchange ActiveSync
4) Type in the email address and password and click Next
5) Type in the Domain\Username, Server
Check Use secure connection (SSL)
Check Accept all SSL certificates
port should be 443
6) Click Next and give the account a name.
7) Click Next and you are done.
NOTE: Mine is Asus Zenfone 6 and Android version is 4.4.2