Outlook "0x80040900" error , Wrong port?

[Geroe]

Hello friends, i am having server connection errors with outlook, i am using 25 port, could it be the reason? Moat of the time mail works perfectly, but sometimes i am starting getting this send/received errors which resolves instanlty if i change the IP address for exampl, using cellular network. Could this be hosting issue or something wrong with configuration, like port as i mention above?

 

[Richard G]

You have to ask your host about that. This is a support forum only for admins and resellers of Directadmin.

However, shortly said, it might be a port 25 block with your ISP. Normally if you change your port in Outlook to port 587 you should be fine.
Also ask your host, it might be that you do or don't need ssl/tls on port 587 to make connections.