Error in Apache logs: "ModSecurity: JSON support was not enabled"

Symptoms

• The following error appears in the Apache log that could be seen at Domains > example.log > Log in Plesk UI or directly on the server at /var/log/httpd/error_log : 

CONFIG_TEXT: ModSecurity: JSON support was not enabled [hostname "example.com"] [uri "/wp-json/notificationx/v1/notice/"] [unique_id "Y@ELjOjkojqzjiuIAB6puAAAANA"]

• API queries using JSON format are not processed by the web application.

Cause

The ModSecurity package provided by Plesk does not have built-in JSON support. It was considered as a bug PPP-59884 and it's planned to be fixed in the next version of Plesk 18.0.51.

You may track changes in the Change Log.

Resolution

Until the bug is fixed, disable ModSecurity rules as per the steps in: https://support.plesk.com/hc/en-us/articles/115002531753

This solution does not have an impact on server security, since this rule is only used for optimizing data processing.

Note: possible rule IDs are: 77350039 or 77316736, the exact rule IDs could be found in the Apache error log, here is an example:

CONFIG_TEXT: plesk/REQUEST-949-BLOCKING-EVALUATION.conf"] [line "57"] [id "77350039"] [msg "Inbound Anomaly Score Exceeded (Total Score: 5)"