Recent problem - beginning this week. When I try to sign in, App doesn't recognize my password. I execute the "Forgot Password" steps, resetting the password on my phone, and get two green check marks -- Good to Go! When I enter that password on the Roku App on the TV screen, I get "Invalid Credential."
You can repeat this cycle with new password resets, entering into the Roku app until the cows come home. It always ends up with "Invalid Credential."
My account is current (monthly billing with authorized, on file and current credit card), my Roku is up to date and no other channels or services we subscribe to are having any difficulties.