I recommend that you try restarting the machine before proceeding with the recommended troubleshooting procedures for this problem. Remove the Roku device from your TV and unhook it from its power supply before turning it off. Turn on the TV and connect the Roku device after waiting at least a minute. This will refresh the operating system as well as erase any faulty temporary data, and it is quite successful in resolving most software problems.
This difficulty can be caused by a variety of causes, including a server failure or a problem with the network security protocol. The troubleshooting procedures to resolve this issue are listed below.
Check to see if the Roku server is up and running.
In this scenario, the first thing you should do is see whether there is a server outage or if there is any server maintenance going on. If you want to see if there is any server maintenance going on, go to https://www.roku.com/en-gb/maintenance. To see if the Roku servers are up and running, go to https://downdetector.com/status/roku/.
Change the security protocol for your network.
The Wi-Fi security protocol is one of the reasons why this problem happens. If you're using AES, consider switching to WPA2-PSK (TKIP).
* Enter the IP address of your router in a browser to see its settings. This address is usually located on the router's back panel or in its manuals. It should be ‘192.168.8.1' most of the time.
* In the settings, go to Wireless or Security and make sure the security option isn't set to AES. It's possible that it'll be WPA2-PSK (TKIP).
* After you've changed the security mechanism, try connecting to the network with your Roku using the new settings.
Check to see whether the Roku error code 003 still exists.
Make use of a hardwired connection.
If the preceding procedures fail to resolve the issue, connect the Roku device to the router through an Ethernet connection rather than a wireless connection. This manner, you can rule out the possibility that the WiFi connection is the source of the issue.