[Symptoms]
Consider the following scenario:
- You have a Microsoft Exchange Online mailbox user account.
- You have an Android phone that supports Exchange ActiveSync.
- When you add the mailbox account on the phone, you input a Microsoft Exchange Online server name with the https:// prefix in the Server field. For example, you input “https://red001.mail.microsoftonline.com” (without quotes) in the Server field.
In this scenario, you cannot click the “Next” button to proceed with the configuration.
[Solutions]
Remove “https://” prefix. For example, just input “red001.mail.microsoftonline.com” (without quotes) in the server field. Check the “Use secure connection (SSL)” check box and proceed with the configuration.
[References]
http://www.microsoft.com/online/mobility/exchange-activesync.mspx
Here blow is a list of server names of for Microsoft Business Productivity Online Standard Suite (BPOS) accounts.

Courtesy of http://richfrombechtle.wordpress.com/2010/02/25/exchange-online-android/