Idiomatic expressions. Review 2.

In 1991, inventor Travis Baylis saw a TV documentary showing how the lack of communications infraestructure in rural Africa was an obstacle to the promotion of healthcare and disease prevention there. Healthcare workers were coming up against a brick wall in their effortsto use education to stop the spread of deadly illnesses. Baylis immediately saw a way to address the issue : provide low-cost radios to rural populations. The problem would be powering them.  Taking up the challengue 

the lack of communication... was an obstable to the promotion... come up against (=encounter) a brick wall (wall made of bricks) be like talking to a brick wall  to hit a brick wall ( figurative) meet an obstacle to take (sth) up: aceptar, comenzar