Follow the steps below if the Iridium 9555 is displaying Check SIM or Insert SIM error.

Solution 1: Remove SIM card

1. Remove the battery by sliding up the release clip and pulling the battery out. See the diagram below for additional assistance
2. 
   
3. Note the position of the cut corner on the SIM card
4. Remove SIM card
5. Obtain a soft cloth or contact cleaner
6. Wipe gold contacts on SIM card

Solution 2: Insert SIM card

1. Insert SIM card
2. Make sure the cut corner is on the same side displayed on the SIM card slot
3. Insert the battery and press firmly to lock it into place
4. Press and hold power button
5. The phone will power on and begin to search for the Iridium network