041.40 indicates an incorrect password - make sure you are entering the password correctly.
Sometimes firmware updates in either modems/routers/gateways or client devices (like a Roku) can make certain password characters no longer viable, or can change wireless parameters (especially with 5Ghz) causing this to occur, so you might try changing your SSID password and/or verifying your 2.4Ghz and 5Ghz settings.
Since your 4620 is dual band, you might also try separating the 2.4 and 5Ghz SSIDs, so you can connect to one or the other (assuming they arent already separate).
