Identify that connector - Is it reusable?
2 possible issues; contact force and contaminated contacts from skin oil or humidity.  ( unlikely broken SMD solder joints but possible, if you press on board connector only without stress on FPC and that works.)


The receptacle and plated FPC contacts must both be gold plated but this comes in a wide range of quality and corrosion may still be possible in high temp/humidity with ocean salt spray in the air.

These are gold plated Flex printed circuit contacts or FPC.  They come in a wide range of FPC thickness from 0.2mm and up.  If the replacement has a thinner FPC then the contact tension is unreliable.  Putting a polyamide tape spacer ( which also come in different thicknesses) might work but tolerances between won't fit and too lose are tiny.)

Suggestions

Feel insertion force for tiny snap fit from edge of flexible thin polyamide FPC on the sloped receptacle spring contact. If none then a spacer might be needed thinner than the board using special tape called Kapton that looks like the FPC cable.

Clean FPC gold contacts with "pink pearl" pencil eraser.