The message send failed means that for one of many possible reasons you can’t iMessage that particular contact. Their phone can be turned off, no signal, etc. They can even have switched to Android and not deactivated iMessage first.

What does it mean when a text message says failed?

FAILED = Service provider did not accept the message of the carrier and delivery is not possible. Don’t be jarred, this is an easy fix. A messaging carrier might reject the text due to technical issues rather than human error.

Does message send failure mean im blocked?

The message sends as normal, and you don’t get an error message. This is no help at all for clues. If you have an iPhone and try to send an iMessage to someone who has blocked you, it will remain blue (which means it’s still an iMessage). However, the person you’ve been blocked by will never receive that message.