Why is my nether portal not working?

Your nether portal might not be working due to a few common issues. First, ensure that the portal is built correctly with a minimum of 10 obsidian blocks in a rectangular shape, and that it is activated with flint and steel. Check that there are no blocks obstructing the portal or placed incorrectly, and ensure you’re standing in the correct dimension when trying to enter. Additionally, make sure you are in a version of minecraft that supports the Nether, as some older versions might have limitations.