if u have not been migrated, tx3mini shud work with this app version.
it works on my tx3max, tx5max, tx3 s905x3:
https://www.apkmonk.com/app/com.huawei.pad.tm/

BUT... make sure it is using WIFI. LAN connection will not work.

when u install that one from playstore, what happens?

v7.9.11 works fine with tx3 if u r not migrated, still on old silver or white STB as main.
likely u have been migrated or u r new customer... v7.9.11 will be irrelevant to u.
there must be one version that works for u.
try the modded ones v1.1.x, v1.2.x given here:
https://forum.lowyat.net/topic/4726997/+1900
or this new v1.3.1:
https://play.google.com/store/apps/details?...tm.playtv&hl=en

this unifi playtv app story is a big mess... becos they never consolidated the STBs and apps for 10 years.
there are like 3 types of silver boxes, 3 types of white and 1 new black.
apk versions, i know there are at least 3 types.
add to that a dozen categories of customers, diff packs, some STB, some no STB.
worst of all, unifi does not communicate much with their customers.
so, u just need to try any apk u find.

Hi AVFAN, I bought the unit from linglang in April 2020. How to know whether the unit is migrated or not?
As for the playstore, u just cant install as TX3 is not compatible
I hv tried modded ones v1.2.x which was worked over the past 2 months. It just stop working recently which asking me to upgrade.
Let me try new v1.3.1 and update again
Thanks..

it is about yr unifi tv account migrated or not, not the box!

ya, try the latest one.

my exp, tx3 using official apks work, no need modded.

unless u r trying to do something exotic like using a version not meant for it.

u have confirmed what i have always said - tx3 works with official apk, no need modified.

same with astrogo.

i have 3 tanixes - all >1 yr old now.

tx3mini - best value for money; if u do not need big memory for plenty apps; good for axtrogo, unifiplaytv; wifi weak.

tx3 s905x3 - big memory (may be underutilized); good for axtrogo, unifiplaytv; wifi weak.

tx5max - better PQ, smoother, great wifi; cannot do axtrogo.

the key word is "suddenly".

if u did not move the box to another tv, did not change hdmi cable, that alludes to something weirdly wrong.

sellers suggestions are correct, try those.

before u junk it, try one last thing - do a pin reset to factory setup/last firmware.

if still no good, it is confirmed done with.

If you have the QZ or BZ version of the TX3 (not mini), there's the option of trying flashing a custom firmware. But that carries risks, and forget about sending it back to the seller with that FW installed. PM me if you want further info.