support ticket number:ID#5213146
It was pretty interesting. The technician was trying to right click the vcenter server from the UI of Veeam one , however there was no drop down menu.
Finally changed the display settings of Windows 7 from Medium 125% which is the default to smaller and then the drop down showed up once he right clicked the vcenter server.
I just retyped the credentials again and it started working as usual.Apparently there seems to be some sort of bug in the UI which he said would be fixed in the next version.