I picked up the HTC Trophy this week running Windows Mobile 7.5 aka Mango. Unfortunately, if you do not sync and setup your accounts in the right order the Facebook Chat integration will not work.
Steps to Resolve
- Visit Settings > email+accounts and long press on your synced Facebook account to delete it.
- Using a computer, visit Live.com and sign in with your Windows Live ID.
- On your account homepage, find the "Connect your services" box, and select Facebook. Follow the prompts to connect your accounts together.
- Once connected, return to your account homepage. You should now click on the small Facebook icon that now appears under the heading "Messenger social". Ensure all boxes are checked off on the page it brings up.
- Login to Facebook on your computer, and ensure that your chat status is set to "Available". Also, some people have noted that disabling secure browsing helps, but I cannot confirm or deny this. You can find this setting under Account Settings > Security > Secure Browsing.
- Finally, add your Facebook account back to your phone and give it 5-10 minutes to sync up. Your Facebook Chat will be available under Messaging > Online. If you still cannot see anything, click settings on this page and ensure Facebook Chat is enabled.
Feel free to comment with any other tips or fixes, Good Luck!