Troubleshooting: Why Your Crying Obsidian Portal Won't Activate

Check the Frame Shape

The most common reason a portal fails to light is an incorrect frame. The interior opening must be exactly two blocks wide and three blocks tall. That means the frame is four blocks wide and five blocks tall if you count the frame blocks themselves. If your opening is only one block wide or two blocks tall, the portal will not activate. Count the empty space inside the frame, not the frame blocks.

Verify Block Types

Every block in the frame must be either obsidian or crying obsidian. If you accidentally placed a block of stone, dirt, or any other material, the frame is invalid. Break the wrong block and replace it with obsidian or crying obsidian. Also make sure you are not trying to use crying obsidian in a version of the mod that does not support it; if you have the mod installed correctly, both block types work.

Lighting the Portal

Use flint and steel, a fire charge, or any other vanilla ignition method on the inside of the frame. Aim at the bottom interior block. If the portal still does not light, try breaking and replacing one of the frame blocks to force the game to re-check the shape. Sometimes placing a block inside the opening and then removing it can also help. If all else fails, rebuild the frame from scratch, ensuring the dimensions and materials are correct.