chore: add domain whitelisting instructions to FAQ (#271)

Author: filipelima18

packages/projects-docs/pages/faq.mdx

@@ -98,6 +98,14 @@ Devboxes are part of our evolved CodeSandbox experience, so we highly advise you
 If you encounter this error when importing or committing, check your sandbox or
 repo for large binary files and remove them.
 
+## Which CodeSandbox domains should I whitelist on my firewall to ensure CodeSandbox loads correctly?
+
+If you suspect that your Sandboxes/Devboxes aren't starting due to your firewall rules, try whitelisting the following domains:
+
+- `codesandbox.io`
+- `*.csb.app`
+- `worker.codesandbox.io`
+
 ## Can I use a database on CodeSandbox?
 
 Yes, you can use any database that has a Docker image available with a Devbox. Some popular databases with Docker images include MySQL, PostgreSQL, MongoDB, and Redis.