How to check SMSC Number in iPhone.
I have tried
*#5005*7672#
**5005*7672*12063130004#
its showing as Error performing request Unknown error
iPhone 7
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There is no SMSC (SMS service center number) on an iPhone.
Carrier Update (Required): Released by your Cellular Service provider (Carrier Update), affects your Outgoing / Incoming calls, SMS, Data etc..
How to Update Carrier Settings
You can manually check for and install a carrier settings update with these steps: Make sure your device is connected to a Wi-Fi or cellular network. Tap Settings > General > About. If an update is available, you'll see an option to update your carrier settings.
Update your carrier settings on your iPhone or iPad - Apple Support