I have installed Hmailserver in one of the computers in the LAN network. Also installed Wampserver so that other users can reach to this particular computer. Created a local domain inside Hmailserver. Now, using manual setup I can connect most of the Thunderbird users to the domain and they can exchange mails properly. However, for some thunderbird users given the same manual setup, thunderbird not able to find the settings. I have attached Hmailserver diagnostics report and thunderbird messages. You can see that, for the same setting it is behaving differently in different computer. Please let me know if any further information is required. P.S. I have tried different versions of thunderbird but not worked so far.