Exclamation Point over the Cellular Data Icon + Impaired Data Connectivity (5.1 stock Nexus 5)

[Orpkyut]

UPDATE 9 Apr 2015 1 new solution has seemed to have resolved the problem (for now, let's see how long it lasts). See below, will updated if things change.


=====SYMPTOMS=====
Just a few days ago (several weeks after I received the Over the Air (OTA) 5.1 Lollipop Update, my cellular data service icon began showing an exclamation point icon where there would normally be LTE or H.

In using apps, data connectivity is only fleetingly present, but is generally impaired at best.

For example, on the Home screen's Google Now page, I can see updated headlines and articles, but when I click to open the article in Chrome, Chrome tells me "No Data Received."


=====DEVICE CONTEXT=====

• Nexus 5
• Stock
• Lollipop 5.1
• Build Number LMY47D

=====REMEDIES I'VE TRIED=====

• Rebooting
• Disable / enable Cellular Data
• Remove / re-insert / reseat the existing SIM card
• Fully replaced with brand new SIM card from carrier store (this resolved the issue for about 1 day - the issue returned the next day after I turned WiFi on, connected to a WiFi network, then disconnected from the WiFi network)
• On the phone dialer, enter star#star#4636#star#star > Phone Information > turn cellular radio off / on again
• Wipe Cache Partition
• APN Settings > changing to another APN > reboot
• APN Settings > Menu > Reset to Default > select my carrier APN again > reboot
• Disabling WiFi radio, rebooting
• Toggling Airplane Mode, rebooting
• Switching to Preferred Network = 3G, then back to LTE: THIS HAS RESOLVED THE PROBLEM (for the past 30 minutes at least...will update if things change.

What is the solution?

 

[SpookDroid]

This seems to be an issue with how Lollipop checks for connectivity to Google Services. Not really sure how to fix it (or if fixable at all), but let me check the backlog... it's been a while since I've heard about this issue.

I know it's not the solution you probably want, but have you tried factory-resetting your phone?

 

[Orpkyut]

This seems to be an issue with how Lollipop checks for connectivity to Google Services. Not really sure how to fix it (or if fixable at all), but let me check the backlog... it's been a while since I've heard about this issue.

I know it's not the solution you probably want, but have you tried factory-resetting your phone?

No, I haven't tried that yet.

I'd be more inclined to try it if someone could verify that it absolutely resolves it, and something will prevent it from happening again.

Pretty ridiculous to have to factory reset for what seems like a bug, as I haven't made any modifications to the phone (no custom ROM, etc.)

 

[Greg Monroe]

I toggle the Cellular data off and on when this happens to me and so far that has worked for me. If it helps, I notice that the exclamation mark for my data connection usually only appears when I am streaming audio to the car radio via bluetooth.