Set Jackson up for success. Go back to basics. Do plenty of recall when he's paying attention. Be exciting when recalling, you're trying to make yourself more interesting and fun than anything that could distract.
Even if Jackson decides to come back to you on his own accord, use your recall command. Praise loads and reward with a treat.
As he becomes more confident with his recall he'll begin to return when something is a bit more distracting.
However, do remember, that sometimes they need to get left of steam, finish a greeting with another dog and you need to wait for a gap in their proceeding before you'll get their attention.
Basically, build on easy recall so knows exactly what's expected of him. Keep up the training and they will get the hang of it and be more responsive. :d