Sorry, still sinces hours on how to give feedback... i dont have skills :((((( . Can someone else help us ?

@bastimeyer : i succeded in test, please see result :
PS C:\Users\xxxxx> streamlink https://www.nowtv.com.tr/canli-yayin best
[cli][info] Found matching plugin nowtvtr for URL https://www.nowtv.com.tr/canli-yayin
[cli][info] Available streams: 360p (worst), 480p, 720p (best)
[cli][info] Opening stream: 720p (hls)
[cli][info] Starting player: C:\Program Files (x86)\VideoLAN\VLC\vlc.exe
I don't know the next step for you needed, as no more action from my side possible ? Thanks, best regards

Well, congrats, but I was looking for feedback whether there's any content on that site which does not work with this plugin implementation. As mentioned, there are some geo-blocked streams...

Going to merge this now... Apparently, the news channel wasn't available at the time, but it's now, and it's working fine. I couldn't find any other content that's not working, but if I'm wrong, then a new plugin issue should be opened (if it makes even sense).

Hello @bastimeyer thank you again for your updates. Yesterday url access was Ok but since today we get Exception Error :
streamlink.exceptions.PluginError: Unable to open URL: https://www.nowtv.com.tr/canli-yayin (HTTPSConnectionPool(host='www.nowtv.com.tr', port=443): Max retries exceeded with url: /canli-yayin (Caused by NameResolutionError("<urllib3.connection.HTTPSConnection object at 0x7f3b6e86d610>: Failed to resolve 'www.nowtv.com.tr' ([Errno -3] Temporary failure in name resolution)")))
More worklow info : https://github.com/ipstreet312/freeiptv/actions/workflows/nownew.yml
I can't found more info on that "name resolution" issue whitin the project even a similar issue for helping me to resolve it.
Is there a workaround or a possible fix ? Thank you, best regards

It's a DNS issue. Only one of their name servers is returning an A record for www.nowtv.com.tr.

Nothing can be done about it here.

Force IPv4:

$ streamlink -4 'https://www.nowtv.com.tr/canli-yayin' best
[cli][info] Found matching plugin nowtvtr for URL https://www.nowtv.com.tr/canli-yayin
[cli][info] Available streams: 360p (worst), 480p, 720p (best)
[cli][info] Opening stream: 720p (hls)
[cli][info] Starting player: /usr/bin/mpv
[cli][info] Player closed
[cli][info] Stream ended
[cli][info] Closing currently open stream...

$ streamlink -6 'https://www.nowtv.com.tr/canli-yayin' best
[cli][info] Found matching plugin nowtvtr for URL https://www.nowtv.com.tr/canli-yayin
error: Unable to open URL: https://www.nowtv.com.tr/canli-yayin (HTTPSConnectionPool(host='www.nowtv.com.tr', port=443): Max retries exceeded with url: /canli-yayin (Caused by NameResolutionError("<urllib3.connection.HTTPSConnection object at 0x7f576e662270>: Failed to resolve 'www.nowtv.com.tr' ([Errno -5] No address associated with hostname)")))

Thanks a lot for your help contributions.
py line added : session = streamlink.session.Streamlink(options={"ipv4": True})
working fine finally. Bests !