Not registered on network?

[Deleted User]

Yesterday, a family member rang me on our landline and informed me they couldn't contact me via my android . After the call, I endeavoured to call them from my android.

Up came the message "Not registered on network".

To my knowledge I'd done nothing. I googled and discovered I should switch  "airplane mode" to on then off. This cleared it but why?. Do you have an explanation or if that had failed, what then?. 

PHK

There are a few possibilities.

Some versions of Android have a bug when on certain networks that can cause this.

There may have been a network issue. (which required disconnecting and re-connecting)

The SIM might be going or loose in the socket

You local cell may have reached capacity and so unable to register the handset

There might be a component failure in the phone.

If you let us know the Make and model of phone and what Androud version its on plus your network provider then we might be able to narrow it down.