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No 4G after returning from abroad.

Rising Star
Posts: 97
Thanks: 12
Fixes: 1
Registered: ‎04-02-2011

No 4G after returning from abroad.

Had a problem with my SIM - I was recently in Spain and used it for both data and calls while roaming, everything was fine out there.

When I returned I noticed that my phone would never connect to 4G, only 3G. Had an on-line chat with Plusnet and tried resetting my APN data without any luck and they decided that connecting to a foreign network had corrupted my SIM. They sent a new one and as soon as it was activated it connected to 4G straight away.

So, everything is fine now but I was wondering...

1) how can connecting to a foreign network 'corrupt my SIM'?

2) Is this going to happen every time I go abroad? It'll be a right pain if I need a new SIM each time I return.

Plusnet Alumni (retired)
Plusnet Alumni (retired)
Posts: 929
Fixes: 31
Registered: ‎25-11-2016

Re: No 4G after returning from abroad.

Hi alanonplusnet,

Thanks for getting in touch with us! I'm glad that you're now back up and running with your 4G service and I'd be more than happy to answer any queries that you have! In reply to your questions:

When you arrived in Spain and registered to a foreign network, your SIM would have adjusted to the settings required to establish a connection with the local masts in Spain. On return from Spain, your SIM would again need to revert back to the settings needed to connect to the UK networks and this often requires a re-boot. The re-boot consists of the following:

  • Turn the handset off
  • Take the SIM card out
  • Leave it for a couple of minutes
  • Replace the SIM card
  • Turn the handset back on

This would refresh the signal to the SIM card and should apply the settings required. There may be some cases as to when you're required to input the APN settings manually or manually search for a UK network to connect to. 


In conclusion, this does not necessarily mean that when you travel abroad your SIM is 'corrupted', it just means that your SIM has to adjust to the settings required in order to connect to a local foreign network.

This shouldn't happen every time you travel, your SIM may just need to be manually re-booted in order to re-connect with the network. 

Hope this helps!

- Rebeka Smiley