You could have one of several issues;
1. Antenna coax to Front TV is not connected or is damaged.
2. Front TV is set for A/V or Satellite-In rather than Antenna.
3. Front TV has tuner failure. Repair or replace.
Diagnose by insuring, via On-Screen Menus, that the front TV is set for Antenna, not Digital, or HDMI, or Video. If not, switch to Antenna and perform Scan.
Substitute a known good TV to see how it performs. If it works OK, suspect #3. If it has the same problem, suspect #1
Good Luck
Mike
Retired Electronics (TV) Tech and Consumer Electronics Service Business Owner.