Unfortunately, data reception and speeds may not be as good indoors or in a car. Signal can be affected by buildings, trees and even weather conditions. 

To ensure there are no known faults at your postcode, check the current status of the network  here: https://status.o2.co.uk/

If you've had no issues previously with indoor signal at the same location and no faults are shown online, it's possible your phone or SIM card may be the cause of the problem. 

• Try switching your phone off and on? Better still, do that and remove and reinsert your SIM in the process.

• No improvement? Try your SIM card in another unlocked or O2 locked phone? Doing so will help us identify if the issue is signal related or hardware related.

If you have a compatible handset¹, a connection to a WiFi service and your data profile is correctly configured to the plan.com data service², WiFi calling is available to you. This facility will bypass the cellular network and any related signal issues.

¹any iPhone model launched after and including iPhone 6, with up to date operating system and any Samsung Galaxy model launched after and including Galaxy S7, with up to date operating system.

²to configure your data service, follow this guide for your operating system: https://www.plan.com/apn-settings