Here's a complete step by step cell phone repair tutorial on how to fix Nokia X2 mobile phone insert sim card problem or hardware failure issues. Before proceeding this process make sure to completely check the Sim card connector pins connections, make sure if it is free out from dust, molds, corrosion or any foreign objects.
The picture guide below shows the components ( highlighted square pink color ) where the line paths of the sim card connector goes through. You can check on each value or replace them if found faulty.
Now, the X2 uses the EMI Filter to protect from risk of EMI and ESD interference.
Before replacing or removing the EMI Filter make sure to check first the power supply voltage that feeds to the SIM connector Pin 1. Check the line paths in between those lines from C2215 to R2311 and to sim card connector pin 1.