If you receive an error without a code when trying to connect to Kaeru Gallery like "Failed to connect to the server", often this is caused by use of alternative DNS servers such as those for Sudomemo, Wiimmfi, or Kaeru WFC.
Try visiting https://flipnote.kaeru.world in your 3DS browser (type the full URL and accept any security warnings, this is normal). You should see a 'Connected to Kaeru Gallery' page appear; if this is not the case, check your DNS settings and try again. If you see a server error, such as 'Internal Server Error' or '404 Not Found', contact Kaeru support.
If the issue persists, contact Kaeru support, as there may be server maintenance. Additionally, if you encounter this error message whilst using Kaeru Gallery after connecting successfully, check your Internet connection, try whatever you were doing again, and contact Kaeru support if the issue persists.
Changing custom DNS settings
Custom DNS servers often only work for connecting to a few specific websites for security reasons, so you'll need to disable them before continuing.
Open System Settings -> Internet Settings -> Connection Settings, select your connection, choose 'Change Settings', scroll to the next page and select DNS.
Here you can either choose 'Yes' to 'auto-obtain DNS' from your router (recommended), or otherwise you can use Cloudflare's public DNS server.
For this, choose 'No', select 'Detailed Setup', choose 'Primary DNS' and type in '1.1.1.1'. For 'Secondary DNS', type in '1.0.0.1'.
If you want to use Sudomemo or Kaeru WFC in future, you can always change the DNS settings back again. We're working with Sudomemo to try to reduce this hassle, so stay tuned for further updates.