Question Connection to Data Plan/Internet Slowed to near Zero After Recent Updates

[AA040371]

Phone info (as reported by phone settings)

-- Model: Xiaomi MiMix 2s (M1803D5XA); https://www.gsmarena.com/xiaomi_mi_mix_2s-9067.php
-- Bootloader unlocked
-- Android version: 10 QKQ1.190828.002
-- Security patch level: 2020-12-01
-- MIUI version: Global12.0.3 (stable); this is manufacturer custom/required UI, not able to be turned off or replaced (AFAIK)
-- Mobile Service provider: T-Mobile ()
-- VPN: Cloudfare 1.1.1.1 (WARP off, for now); Maybe DuckDuckGo when browser is open? (not quite sure...sigh)
-- Mobile threat defense: Sophos Intercept X

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Older phone (obviously). Has been working fine in all respects important to me up until very recently. I generally keep updates off and then go in every few months to update specific ones, or ones that won't let me use until I do (e.g. banking apps). I updated a large group of apps very recently, pretty much all of them except for the truly useless-to-me ones like Accessibility, Calendar, Lens, etc. After that set of updates completed followed by a reboot, when I went to connect to my data plan/internet (i.e. Wi-Fi off, Data on), the download/upload speeds had drastically decreased to virtually zero (e.g. .5, 1, 5, sometimes 10 or 20 KB/sec), i.e. to the point where I can't even run Ookla Speedtest or any other similar app to determine what actual speeds are.

I am a little confused about various settings and what I am seeing in SIM Cards/Mobile Settings. For instance, in the Mobile Network settings sub-menu of my SIM card, I see choices for T-Mobile including ones for 4G and 2G, but I only seem to be able to connect to 2G? Similarly, I have choices in Access Point Names sub-menu, but am unclear what it should be set to or if I should change the setting? And similarly under Preferred Network Type I have selection of LTE, 3G and 2G Only (2G Only was selected when I initially entered menu, but I believe my phone works over LTE as well.

I guess my questions are:

1) Are there any known current issues with T-Mobile service that would have coincided with my set of general updates several days ago, i.e. is my decreased data plan speed a coincidence? I tried searching, and calling them, but was not able to get any answers.

2) How might I go about troubleshooting, e.g. an app that helps with something like this; or some sort of test plan to step through; or obvious settings to double-check?

3) Any other observations, opinions, suggestions anyone might have (without being silly like telling to get a new phone).

Thanks...

 

[methodman89]

Have you cleared the cache and rebooted?

 

[AA040371]

Have you cleared the cache and rebooted?

"Cleared the cache?" If you mean the browser cache, it is set to clear almost everything including cache automatically when I exit...If there is another cache for phone in general that needs to be cleared, I may not be aware of it.

"rebooted?" Yes, several times, after each change to SIM/Mobile settings (just in case...)

 

[B. Diddy]

Welcome to Android Central! methodman89 was referring to wiping the system cache partition, which can sometimes be useful for general glitchiness, but this is less commonly available on more current phones, since most manufacturers have shifted towards having dual A/B partitions (which allows for seamless updates). Your phone does not appear to allow system cache partition wipes: https://www.hardreset.info/devices/xiaomi/xiaomi-mi-mix-2s/

Are you using T-Mobile in the US, or elsewhere in the world?

 

[AA040371]

Welcome to Android Central! methodman89 was referring to wiping the system cache partition, which can sometimes be useful for general glitchiness, but this is less commonly available on more current phones, since most manufacturers have shifted towards having dual A/B partitions (which allows for seamless updates). Your phone does not appear to allow system cache partition wipes: https://www.hardreset.info/devices/xiaomi/xiaomi-mi-mix-2s/

Are you using T-Mobile in the US, or elsewhere in the world?

Thanks...that's useful insight re: system cache and HardReset site

I am in U.S. I can list the APN available to me as reported by phone if helpful? Probably not...

re: HardReset, I see I can reset all network settings...would doing this be at all helpful, or just a Hail Mary? I generally dislike the scatter gun solution approach, though, especially since it seems I'd have to redefine a bunch of stuff to get phone back working how I want it.

 

[B. Diddy]

Resetting network settings is certainly a reasonable thing to try.

Also, try turning off your VPN -- that always has the potential for slowing things down. You could also try changing your DNS to either Google's or the default.

 

[AA040371]

I'll try, then. re: VPN and DNS, I can also stop or remove those apps, but they were in place before I did the updates I referred to in OP. And they are currently turned off, which may or may not mean anything...sigh.

What I really wish I could do is exclude anything T-Mobile/carrier related before I screw around with phone and settings. Not sure if worth mentioning, but I am on a prepaid plan with T-Mobile. My data usage per month is tiny, like 25 GB for current month.

 

[B. Diddy]

I'll try, then. re: VPN and DNS, I can also stop or remove those apps, but they were in place before I did the updates I referred to in OP. And they are currently turned off, which may or may not mean anything...sigh.

What I really wish I could do is exclude anything T-Mobile/carrier related before I screw around with phone and settings. Not sure if worth mentioning, but I am on a prepaid plan with T-Mobile. My data usage per month is tiny, like 25 GB for current month.

Ok, but what's the monthly data limit for your plan? If it's <25 GB, then you're probably being severely throttled due to exceeding the monthly allotment.