I am having trouble connecting my MI HMI to Configuration Manager, any suggestions?

Check your units id matches the id set for the panel in the software,
this is located in the 'panel properties' within Configuration Manager.
Check your cable works, it should be a standard RS232 cable (23, 32
and 55), make sure the cable works with some other software.
Check that the unit itself is set to RS232 and that the correct port is
selected, these selections are changed with the F2 and F4 keys on the
HMI.
Right click on the panel within the Configuration Manager tree, and
select 'disconnect', then 'get connected' and try again.