So I was tuning my newly acquired bike today and working with all 8 gears on the rear derailleur. I managed to properly set the high limit screw as well as cable tension so all gears shift smoothly from 2-7. However, when I try to shift to 1st gear, the derailleur won’t move and neither will the shifter. The cable tension is too tight. I also tried manually pushing the derailleur by hand and I can jusssssttttttt get it to shift into first, but it requires a lot of pressure. The only effect adjusting the low limit screw has had is that if it is too loose, it won’t shift from 3rd to 2nd. Tightening it anymore doesn’t shift it from 2nd to first.
I briefly inspected for alignment and from eyeballing it things look OK, but I am not too sure.
What are some things I can do or try and what should I be looking at if something needs fixing?
Thank you guys for your help.