Scheduled arrival time was 1150AM in SFO (international arrival).
My flight landed around 1140AM. However, the gate was occupied by another United aircraft. So we waited 30+ minute on the tarmac and arrived at the gate 1230PM.
I missed my connection. I was supposed to arrived in my final destination around the midnight on the same day.
I was rebooked on the red-eye flight (10hr 50min lay over in SFO) and arrived in my final destination the next day .

I emailed to United asking e-certificate. United insisted that "we aren't able to provide compensation for disruptions as a result of weather, air traffic conditions, or other circumstances beyond our control"

Is this considered as delay from air traffic condition?

I contacted United again and now I was told "The reason for the delay is due to Air Traffic control airport conditions."