Please try the following troubleshooting steps first, as they may resolve the issue.
・Your network connection may be unstable. Please check your internet connection or try connecting to a different network to see if this resolves the issue.
・Delete the Nintendo Switch version of Pokémon HOME, then redownload it from the Nintendo eShop using the Nintendo Account you used to download it originally.
Following this, launch the Nintendo Switch version of Pokémon HOME again using the same User account that was experiencing the error and check if the issue has been resolved.
*Please do not delete your account from the mobile version of Pokémon HOME. If the account is deleted, it cannot be restored.
How to Delete Game Software on the Nintendo Switch
1. Highlight the icon of the game you want to delete on the HOME menu and press the + button (or the - button).
2. Select "Data Management" and then "Delete Software."
How to Redownload Game Software from the Nintendo eShop
1. Select "Nintendo eShop" from the HOME menu.
2. Select the User (Nintendo Account) that was used to purchase the software that you wish to redownload.
3. On the Nintendo eShop, select the User icon in the top right corner.
4. Choose "Redownload" and select the software you wish to redownload.
*When deleting game software, please take care not to delete any game software other than Pokémon HOME.
*Please note that the Pokémon HOME game software does not store data about your deposited Pokémon, so even when deleting Pokémon HOME using the steps above, your deposited Pokémon will remain intact.
If the issue persists after performing the above steps, please wait approximately 24 hours before attempting to log in again.