Can you flesh that out a bit? Which radio stations? Do other streams continue to work, and it’s only MyTuner stations? Which Sonos devices are you using? You’re running S2 controller on what device? How are your Sonos connected to your network? What router are you using? 

What “apps”? More than one app or the same app on multiple phones?

only MyTuner not working on all malaysia fm channel

my devices are Arc with 7.1.4 setup, One sl, play 5, Ray, sub mini etc..

only had problem with MyTuner after sonos S2 apps update..

all streaming are no problem

Have they moved to another stream distributor? Like TuneIn, iHeartRadio, etc? Have you contacted the radio stations to see if their internet server that provides the feed is down? 
 

Note that most companies use different servers to feed the distributors than they use for their own web streams. Probably for tracking purposes. 

Conversely, have you reached out to myTuner to see if they’re having an issue in Malaysia?

i find out some station are working but some cant (malaysia station), have email to MyTuner but no result yet..