Konosuba: Fantastic Days is having a busy launch day, so busy that many players are experiencing a timeout error when trying to log in. The 80001 timeout error is the biggest one that plagues people trying to get into the game, but it's not a hard wall keeping you out.
Chances are you won't get error 80001 if you're playing Konosuba: Fantastic Days through Bluestacks or Nox. I have yet to speak to anyone who has encountered the error while playing through an emulator on their PC, although the same cannot be said for those I know while playing on an intended mobile device.
If you're feeling impatient and these solutions don't work for you, try emulating for now and connect your account once you're done reviving, then transfer it to your primary device once you can .
How to Bypass Error 80001 in Konosuba: Fantastic Days
Error 80001 is a timeout error, which places the onus of the fault on Nexon's servers instead of your internet connection. There are certainly things you can do to try to get in, though.
Error 80001 Solution #1: Relaunch the game using mobile data
This is the most obvious solution and, of course, the one you've probably tried more than once.
If you are trying to launch the game using a Wi-Fi connection, try doing it through your mobile data instead. Some people have had better success connecting using their mobile connection rather than Wi-Fi, so give it a try. Don't be afraid to try more than once either.
Error 80001 Fix Solution #2: Reinstall the game
This one is unlikely, but some people have claimed it works and is worth it if you get frustrated. Just reinstall the game and try launching it again to see if it works.
Since there is a large download to install most game data after installation, be aware of what connection you are on during the installation process. Like the first potential fix, some people claim they were able to get in after reinstalling using their mobile data over Wi-Fi, but that's a claim you should probably take with a grain of salt.
The thing is, error 80001 in Konosuba: Fantastic Days is simply a server error and not something over which you have that much control. Try and try again and you should eventually get in, but wait a few days if you don't. There is no emergency. Once you get in, you'll definitely want to reroll, so check out our little Konosuba: FD reroll guide here.