List of steps to reproduce (step by step, including full links if applicable):

• Go to replacer.toolforge.org
• Click on "Artículo aleatorio" (random article)
• A 400 Bad Request Error message appears (see https://replacer.toolforge.org/random)

What happens?:
A 400 Bad Request Error message appears

What should have happened instead?:
Error message should not appear and tool should work properly

Software version (if not a Wikimedia wiki), browser information, screenshots, other information, etc.:
Firefox 96.0