Uploading dungeons on the Nintendo Switch version of Super Dungeon Maker can sometimes present issues. Here are some steps to troubleshoot the problem:
Always ensure that you've played, finished, and saved your creation before attempting to upload it. This can help prevent any uploading errors.
If you have multiple accounts on your Nintendo Switch, it's important that your main account accepts the terms & services of mod.io, our modding platform. Be sure to do this prior to uploading your dungeon.
After you've saved your progress, try restarting the game and then hitting upload again.
We understand that this can be a frustrating experience and we're continually working on improvements to make this process smoother.