I don't know when this issue was posted, but I bought a Roku and tried connecting to my wireless network today with similar problems. After trying the right password multiple times, unplugging the Roku device, and router, and resetting the network stack without success; I connected the Roku with an Ethernet cable to my router.
I created a Roku account and tried to see if I could sign into the wireless network from the app on my phone. Unfortunately, I could not find the network settings on the app. What worked for me was attempting to connect to the wireless network on my TV screen while the app was open on my phone. I chose the network on the screen and it took me to the page for inputting my password, but a typing tab opened up on the app on my phone. I copied the password and pasted it and it worked.
But I saw the issue when I pasted the password. There's a metacharacter in my password and I chose it on the keyboard from the TV screen and it kept failing, but after I pasted the password; I saw that the metacharacter was placed a bit lower than that from the screen keyboard. Copying and pasting it on the app did the magic.
