non responsive after screen replacement

[martin lineberger]

First time here, Hope this goes to the right place. My son has a galaxy Tab A and it is not hard at all to change the cracked screen. Only one connection has to be removed. Ordered an oem replacement, everything went fine but tablet now does not respond to any touch. returned and got another but same results. What am I missing? I've replaced phone screens without a hitch. Thanks for any advice.