I signed up for Sling TV on the web and when I went to the television, I was able to view the programming. However, when I went to a second, and a third TV, I was unable to reach a screen that allowed me to input the username and password. I was only offered links to resubscribe or change my subscription options. I was also offered the ability to watch the free content. I contacted Sling and after considerable effort was finally able to chat with someone who was unable to figure out how to fix the problem. The next day, I tried again, and the day after that. I was beyond frustrated, and today, I decided to just simply cancel the service. I was told that the service would be active until the next bill date. When I went back to the only television that worked with the Sling service to watch programming, the Sling app was no longer on the screen. I went back through the Roku device and added it back and believe it or not I was met with the option of purchasing the service again. There were no options to sign in at all. Frustrated, and in no mood to deal with Sling again, I went to the free content, checked the menu and lo and behold, there was a Settings option. I went into the settings and at the bottom was an opportunity to sign in. I went into that and noted that it had my old email address from years ago when I first had Sling. I put in the correct email address and logged out. When I came back in to Sling, there was an option to login. I did so and entered the correct email address and the correct password and everything worked like a charm. I then went to the other TV and did the same thing and everything worked. I don't have any reason to believe it won't work on any television. If you try this and it works, I am happy for you. There should always be a login screen so that people can put in their correct information at any time. This is an issue that Sling and any other app should make note of. Provide a login screen!
As you discovered, most of the channels/apps on the Roku platform have the login screen under the Settings (sometimes a gear icon).
On other channels/apps though, you will be met with a login screen when launching the app.
It is up to the channel developer how/where to implement these different features.
The Sling login screen is a bit hidden. On similar channels, you may find that you have to press the left arrow button to reveal an animated overlay that will provide menu and settings options. Unfortunately, just have to search around for a bit and familiarize yourself with the different implementations.
Thanks for reaching out!
In addition to what @AvsGunnar mentioned, have you checked for an app update to see if a newer version is available?
Here's how:
If the issue persists, contact app support for assistance. please know subscriptions and content, including Live TV issues, are managed by the channel providers.
Keep us in the loop!
Roku Community Team