What’s the error message? You should be able to find this in your PHP error log.
Ajax doesn`t work on the stage (gitlab), but on localhost all fine
Log – 172.19.0.27 – – [02/Feb/2022:13:21:48 +0000] “POST /wp-admin/admin-ajax.php HTTP/1.1” 500 5
Error in console – Failed to load resource: the server responded with a status of 500
I need the actual PHP error message from the PHP error log on your web server to be able to help you out.
Sorry, I can`t find php_errors.log on the stage (gitlab) or reproduce the issue else somewhere(