You are unable to join an online match and you receive the error code 2618-0501 or 2618-0502.
This error code indicates you were disconnected from the service prior to the matchmaking process starting.
This error may be the result of your wireless network or Internet connection dropping your connection, or your connection timing out.
Power cycle your home network.
Restarting your network devices may resolve this issue if it is related to the devices being unresponsive.
Move the Nintendo Switch console closer to the wireless router.
If possible, place the Nintendo Switch within 3 to 5 meters of the wireless router to improve the signal strength during troubleshooting.
It may be helpful to remove the Nintendo Switch console from the Nintendo Switch dock while troubleshooting, and then return the console when troubleshooting is complete.
Move any metal objects or electronic devices away from your Nintendo Switch console and wireless router.
Metal objects and electronic devices may interfere with wireless signals. If you have any of these, such as filing cabinets, speakers, power strips, glass, or cordless phones, next to your console or wireless router, move them away.
If supported by your router, connect to a different wireless band.
Many routers support both the 2.4Ghz and 5Ghz frequency bands. If your router supports both, set up a new Internet connection and connect to the band you are not currently connecting to. Many routers will have default SSID names that label whether the connection is 2.4Ghz or 5Ghz, but if you're not sure, you can review this information within your router's settings.
Manually enter an alternate DNS.
If the DNS you are attempting to use is not working, entering an alternate DNS may resolve this issue.
Situation Not Resolved:
If you are still unable to connect, this may indicate an issue related to the network environment or router being used.
If you would like to continue troubleshooting potential issues related to the router, contact the router's manufacturer for assistance with performing the following steps:
Updating the router's firmware
Resetting the router back to its factory default settings
If you would like further assistance with the Nintendo Switch console, please contact Nintendo Customer Service.