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

• Go to: https://es.wikipedia.org/wiki/Especial:InvestigateBlock
• Include accounts to block, including one that is previously blocked.
• Click on "Make it prevail over existing blocks/Override existing blocks"
• The error appears.

What happens?:
When using the Special:InvestigateBlock tool, an error occurs that prevents progress: If any of the accounts in the box to be blocked are blocked, the error appears:

"No user was blocked. To make this block prevail over existing ones, check "Make it prevail over existing blocks/Override existing blocks". If the block to be imposed is identical to an existing one, the previous block will not be modified."

Even if the "Override existing blocks" option is checked, the error persists, suggesting that the option is not working.

What should have happened instead?:

By checking the option in question, all blocks should be applied regardless of whether the account is previously blocked. The block override feature is not working, even when prompted to do so.

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