“Read more” tag doesn’t work

Hello people,

I’m inserting the “Read more” tag inside the post text (https://screenshot.net/pt/0gyji0x), but it’s not working.
In the source code, the code appears (https://screenshot.net/pt/8986u2w). But on the web page the text below this tag is not hidden.

Please, could you help me?

Thank you!
Rodrigo