Cannot go back to origin

[SquarelyCircle]

I can't tell why I can't go back to origin in this image. I know that you have to have all the exits/entrances connected... I just don't see what it's talking about here. I don't know what resource truck can't return to its origin. I'm just totally baffled about what to do or click to understand this problem.
https://steamcommunity.com/sharedfiles/filedetails/?id=2087509337

[SquarelyCircle]

I have no idea what I did, but the message disappeared.

[Alex, Master Penguin]

I bet you were still paused before you placed that dirt road, and resuming the game allowed the trucks to find their way back home. If it happens again, please upload the save

[SquarelyCircle]

Originally posted by Alex, Master Penguin:

I bet you were still paused before you placed that dirt road, and resuming the game allowed the trucks to find their way back home. If it happens again, please upload the save

It appeared after the places had been connected for a while.

Thinking back on the situation, I believe it was the railroad that it was referring to, because it disappeared shortly after I finished researching bridges and built the track bridge. Would that message refer to railroads as well as trucks?

[Shran]

Social distancing. :)