Hey @Ton2, thanks for reaching out.
We see you're having an issue with logging in to MTV through your Roku device. Let's help you get back into streaming.
In order for you to log in to MTV through Roku, your TV provider subscription must include the channel to be able to sign in.
If you're still unable to access your content after logging in, I would suggest reaching out to MTV customer support. https://viacom.helpshift.com/hc/en/18-mtv/
We hope this helps. Reach out if you have any more questions!