An error message you may not have seen on your Samsung Galaxy S9 is the following: "Sim card not allowed".
The error message can sometimes appear a few days not at all, then again more frequently. If this error also occurs with your Samsung Galaxy S9, you now have the following options to correct the error.
A quick solution often brings one of the following tips.
Clean the Sim card
Very often it already helps to clean the Sim card or the Sim card slot from dust particles, which are responsible for the above mentioned error
If this doesn't help, continue with our second tip.
Sim card has a technical defect
Try alternatively another Sim card and check if this also shows the error. Often the contact surface of the Sim card is defective or badly processed and leads to the error "Sim card not allowed".
Sometimes it can help to have the configuration file for the Sim card or the smartphone sent again by the provider.
So it is possible that a possibly irrelevant configuration file is overwritten and the SIM card works correctly afterwards.
The configuration file can usually be requested via the provider's Online Service Center.
Quick remedy - aircraft mode
Usually it helps to activate or deactivate the aircraft mode. This causes the smartphone to dial into the mobile network again and the error usually disappears.
We hope that you were able to solve the problem on your Samsung Galaxy S9 with one of the four tips.