run into a stone wall
Also, run into a brick wall. Encounter an insurmountable barrier to progress, as in We tried to get faster approval from the town and ran into a stone wall, or For Allan, learning a foreign language amounted to running into a brick wall.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.