Hey there 
welcome back to the forums! 
Basically, the error means Netlify can’t find the base directory you’ve set up in your configuration. Specifically, it’s searching for a directory called .next at the root of your repository, but it seems like that directory isn’t there.
Now, the base directory is pretty crucial because it’s where Netlify starts looking for all the important stuff like configuration files and build commands. If you haven’t set one explicitly, Netlify just assumes it’s at the root of your repository. Here is some documentation on setting your base directory.
If your project’s build files aren’t sitting right at the root, you’ll need to tell Netlify where to find them. For instance, if all your project files are tucked away in a folder named frontend, you’d need to set your base directory to frontend.
You’ve got a couple of options to set this up. You can hop into the Netlify UI and tweak your settings there under Build settings. Alternatively, if you prefer managing things from your codebase, you can throw a netlify.toml file into the root of your repository and specify the base directory there. Just remember, if you’ve set it in both places, the netlify.toml takes the lead.
Take a look at your repository, make sure that .next directory is there, and ensure it’s correctly pointed out in your Netlify setup. If it’s missing, you might need to adjust your build process to create it, or simply update your Netlify configuration to point to the right spot.
Hope that helps smooth things out for you! Let me know if you need any more assistance.