Some of my residential high-rises have stopped receiving home robots, and I have no idea why

Ok, about 2 blocks of my residential high-rises have stopped getting deliveries of home robots. I have no idea why. There are no traffic jams and all of the related factory buildings are running fine.

To be specific, here’s how home robots would get from my factories to the high-rises.

Exit factory, drive along local road to train station
Get on train, head to city central station
Get off train and onto highway network, drive to nearest local exit
Get off highway, drive on local road to high-rise

The rest of my buildings are getting home robots, but the delivery drivers seem to be ignoring these 2 particular blocks of buildings.

It’s not a huge problem for me, but I would like to see it fixed.

Are these blocks in the city district and is your production high enough?