Without a 1756-LSP Partner module, the 1756-L62S will not talk to I/O modules across the backplane. Without a backplane connection, a ProSoft MVI56 solution will not be able to complete its boot-up routine and will not allow access via its Configuration/Debug port for configuration uploads/downloads or diagnostics.
To correct this situation, you will need to either add a 1756-LSP Partner module to the system or change to a different ControlLogix CPU that does not require a Partner module.