Rebel T7 not syncing strobes?

[freewheel]

Please help me resolve this mystery!  Thanks in advance!

I bought a Rebel T7 to replace an old Nikon camera for studio shooting with a couple of "no brand" strobe lights that I have been using for years. Both cameras are at 1/100s F 5.6, ISO 100, first curtain. The strobe lights are triggered by the built-in flash of the cameras. 

TOP IMAGES: Nikon picture is bright as can be, excess light actually.
BOTTOM IMAGES: in the Canon picture is very dark, you can barely see the subject, even though the the strobe lights actually flashed, the picture is just like the strobe lights were off.  I even tried 1/30s and made no difference.

Other than that, the Rebel is working perfectly.

Question 1: 
if the Canon is triggering the strobe lights, why the light is not being captured?

Question 2:
What would make the Canon work in this setting?   A transmitter? Which one?  A cable to the strobe?

[MikeSowsun]

I should have mentioned that Canon did see the error of their ways and reintroduced the center contact to recent T7 production.  If the OP has one of the more recent T7s, it should make things simpler. 

[zakslm]

Thanks Mike!

[freewheel]

Here it is! does the means this particular camera is a good candidate for a transmitter?