Make sure the axle is well seated in the dropout to maintain the exact position.
Check how much brake lever motion you have, they may be set a bit tight with little clearance.
Most cable discs move on one side only and bend the rotor to contact the fixed pad. You adjust the moving pad with the cable tension and the fixed pad with a central allen bolt adjuster. Check the specs for pad spacing on your model. Some models require asymetric spacing, more on the moving side.