Central Air is Blowing cold air outside
If the unit was working somewhat fine and you were simply doing much appreciated maintenance to restore its past performance, then you mixed up the wiring during the new thermostat install.

If the unit wasn't cooling and therefore prompted the maintenance, then it would likely be that the TXV (Thermal Expansion Valve) needs to be replaced.

If the unit's inside coil was hot, then the Thermostat wiring is screwy...assuming it's set to Cool and not Heat. If the inside coil wasn't hot, then the Thermostat is still wrong, but you fortunately discovered before heating season that the Reversing Valve needs to be replaced.