Grammar fix
come up against
face a difficult situation or problem
to suddenly have to deal with a difficult situation, problem, or obstacle.
phrasal verbB2common

Hear it in context
Notice where the phrase sounds natural.
We came up against a lot of problems when we tried to renovate the old house.
During my studies, I often came up against tight deadlines, which taught me how to manage my time better.
Fix the pattern
One small grammar move makes it sound right.
Not: We came up against with some problems.
Say: We came up against some problems.
No 'with' — 'come up against' takes the obstacle directly.
Which sounds natural?
Tap the one a native speaker would say.
'Come up against' is how people describe hitting resistance; 'encountered considerable opposition' is report-speak.
Build natural chunks
Words that usually travel with it.
come up against + obstacle
- opposition
- resistance
- a problem
- a brick wall