WP error message inside pagination

PHP Warning: Use of undefined constant custom_pagination - assumed ‘custom_pagination’
How to solve such error?
Need help.

Need to post the code that generates the warning, in order for anyone to help you.

Presumably you’ve missed a $ off the start of a variable name, but if that doesn’t help, post the code and someone will help.

Hopefully that’s not on a live website. You should have errors turned off for a live site.

Thank you for the information. I will validate and check PHP.