Devices and simultaneous use are different
Installing an app on several devices does not mean they can all stream at once. One person might alternate between a TV and phone, while two simultaneous viewers have a different need. Consider concurrent streams, not just the number of devices you own.
Do not infer limits from the label
Sadece IPTV offers single-user and two-user groups. Account sharing, allowed connections and same-household or different-network use are not fully defined by those labels. Ask support explicitly before buying, then compare the durations and prices in the appropriate group.
Troubleshoot systematically
If playback stops only when a second device starts, check the account connection limit first. If every device is affected, check the internet connection, app and access details. Note which devices and networks were used and in what order for support. Do not post your username or password publicly.