Hi @Marlowe05,
Welcome to the EE Community
When you say you have a new EE SIM card is this a replacement SIM for a number you already have with us or have you just joined us? Are you unable to call and text also?
Is this happening in one specific area or everywhere you go? Have you checked the coverage checker to see if there are any issues at the moment in your area?
Few things you can check on the phone, first the Network mode in Settings> Connections> Mobile Networks> Network mode and make sure its set to the 4G or 5G mode depending on if your phone is 5G capable.
Check if your phone needs a software update in Settings> Software update.
Try a reset of your network settings in Settings> General management> Reset> Reset mobile network settings and then give the phone a restart.
Alex
