[dasfoto]

I'm having similar problems and it's been getting worse. Had no connection problems before the fix and none sdirectly after the fix, but lately, I'll lose all my data connectivity. If I cycle through Airplane Mode, I'll get the connection back again. Haven't tried anything else yet.

[sparkedfire]

There is a problem with the LTE data connection with this phone.  If you are in a poor coverage area it can get stuck on 1 LTE bar and you won't get any data connection.  There is also a bug where the phone gets stuck in 4G mode.  I am trying to get this addressed by Nokia support.

[clking66]

Same problem for me.  Worked fine for a few months then could not get visual voicemail, send/receive texts, or send/receive email.  Word on the internet was that it was a problem Nokia knew about and could be fixed with a software update.  Tried to update but message said my phone already had all available updates.  Phoned ATT support and was shown how to reset/reboot (hold down the on/off button while also holding the down volume button, keep holding both even when you get a message to slide down to power off until you get black screen, phone will go off and come back on).  This would usually result in data functions returning, though sometimes it would take several minutes, but the problem kept recurring.  Replaced SIM card.  Problem kept recurring.  ATT sent me a refurbished device and I mailed my original one back to them. Same problem with the refurbished device.  Data connectivity disappears.  I keep having to reset/reboot continually to keep voice, text, and email messages downloading and going out.  Nokia won't do anything about it.  They say I can mail the phone to them and they'll have their technician look at it.  ATT says they will override the upgrade I used when I bought the device and let me buy a new phone at the discounted price and restart my contract renewal, but I'm out the money I paid for the Lumia 900.

[clking66]

Nokia won't do anything for me about the problem. ATT will let me buy a new phone at the discount/upgrade price but I'm still out the money I paid for the Lumia 900.

[paulheu]

This does not sound like the same issue as you posted to at all. I'd start by trying another SIM

Also the OS version and firmware revision from Settings>about>more information would help.

Lastly remember we're not Nokia. This is a user to user support forum. We'll help where we can, but we're not Nokia