Cannot log into domain via Expand

[PaddingtonC]

I have an expand 2.3.2 running on Ubuntu 8.04 LTS and it connects to 4 Plesk 9.5 servers of which 2 are Linux 8.04 LTS and the others are windows 2003 LTS. In the past a client could log into the expand control panel and choose click on their domain, then by clicking log into domain they would be automatically redirected and logged into the Plesk server which manages their domain. Now only one server works while the rest give a blank white page after clicking log into domain. I do not know when this started. How can I trouble shoot this?

 

[abdi]

Do you get anything useful in the logs?