Here's a solution for Nokia C3 with Insert Sim Card problem that doesn't detect a SIM card being inserted to it.
This solution guide shows the connection tracks of Nokia C3 sim card pin connector down to the SIM filter IC. You may just refer to the solution below to trace and check each corresponding pin connector connection if trying to fix insert sim card problem on nokia C3.
Nokia C3 SIM card pin connection line paths and filter IC jumper ways
You may check the VSIM and ground pins first before trying to replace the Nokia C3 SIM filter IC.
You can also apply the filter IC jumper solution above to determine if all the line paths were working okay.