Can a poorly connected XLR connection cause a reduced(less loud) signal?

XLR has two signal conductors, if one is not working you loose about 6 dB of output.

Swapping a cable L to R should diagnose if this is a cable issue or not.

I think I have experienced this issue before. XLR's sometimes do not have a very robust grip. On suspect connections I have wrapped the XLR's with tape with extra length attached to top of amp to act a sort of "hoist" that pulls the connector upwards thus reducing sag. This is a commonly known technique for improving the connection of power cable plugs too.

yes.  Like Erik said.

*lose

In my case, similar to yours, it turned out to be the XLR cable itself

Thanks for all the responses.  I have tried multiple new cables, but have also ordered a cable tester, and tomorrow will be able to know for sure about cable.  I have seen other posts on the ROSE HIFI forum that these connectors could be problematic. I have entered a support ticket on that forum. Will let you know what I hear.

@elliottbnewcombjr was your issue on Rose HiFi gear, or something else?

My xlr problems on OPPO video with supposedly great audio.  And cables front my Sony sacd player and cables in out of dual 31 1/3 octave bands. Back to rear everything equal and no noise

make that back to rca ....

Thanks @elliottbnewcombjr 

Yes, I have switched back to RCA, and things work as designed. It’s an “OK” solution, as I purchased and paid extra for, these two pieces so that I could connect them in balanced fashion.

I’ve reached out to ROSE HIFI support, as the problem does appear to be on their end. Rather it be their electronics or connector.

How do I know cables are good, I purchased a cable tester from Amazon.  Love it!  Highly recommended piece of kit for tinkering audiophiles.  See link.

Amazon : Behringer CT200 Microprocessor-Controlled 8-in-1 Cable Tester