Technical Tips and Troubleshooting

Are you using the MIT GUEST wifi network on campus? Don’t use that network, its internet access is very limited. Remove MIT GUEST from your laptop’s list of approved networks, and use MIT SECURE instead.

6.031 systems use Touchstone to log you in, which allows you to either use a browser certificate (the most convenient method) or type your Kerberos password.

First just try restarting your browser. That often fixes a temporary hiccup.

Next try a different web browser: Chrome, Firefox, Safari.

Try deleting your browser’s cookies associated with the site you’re trying to log into.

Try using your Kerberos password instead of a browser certificate. If the password works and the certificate does not, you probably need fresh certificates.

Are you using Windows with an antivirus checker turned on? Sometimes antivirus interferes with SSL connections and causes SSL_PROTOCOL_ERROR in every browser. Try turning off your antivirus checking temporarily to see if it fixes the problem. If so, then look for a way to add the web server to the “allowed” list in your antivirus configuration.

If all else fails, please post privately on Piazza and include the URL you tried to visit, whether you were able to log in with 2-factor authentication, and any error information.

Building and running

I can’t compile or run tests on my problem set.

Make sure you have run npm install in the problem set folder.

`npm test` produces the error `Cannot find module '../lib/cli'`.

In your problem set folder, find and delete the node_modules folder, and then run npm install again.

Navigating and editing

When I see the name of a variable or method or class in VS Code, how can I jump straight to its definition?

Command-click (Mac) or Control-click (Windows & Linux) on the name to jump to its definition. Right-clicking and choosing Go to Definition does the same thing.

How can I easily comment and uncomment parts of my code?

Use Edit → Toggle Line Comment to quickly toggle on or off some lines of code. The keyboard shortcut is Command-/ or Control-/.

Please post on Piazza to suggest more resources or tips and tricks we might include.