Does not come when there is an underscore in the nickname, how to fix it?

Question

PHP

Hello.
How to solve the problem when there is a nickname with an underscore in the body of the response message and because of this, the response does not even come to the bot, example:

$ANSWER = 
"...обращайся за помощью сюда: @admin_panel";

if you remove it, then the message comes, as in the example:

$ANSWER = 
"...обращайся за помощью сюда: @adminpanel";

How can I get a response with a nickname with an underscore? Thanks in advance.