Website or preview in Plesk does not work: HTTP Error 403.0 - ModSecurity Action

Martin Dias

Updated August 17, 2021 18:33

Plesk for Windows Plesk for Linux kb: technical

Applicable to:

Site preview or website in Plesk does not work:

CONFIG_TEXT: HTTP Error 403.0 - ModSecurity Action
There is the following error in the Event Viewer > Application log or under Plesk > Domains > example.com > Logs (for Linux):

CONFIG_TEXT: ModSecurity: Access denied with code 403 (phase 2). Pattern match "^[\\d.:]+$" at REQUEST_HEADERS:Host. [file "E:\/Plesk Data/Plesk Install Dir/Plesk/ModSecurity/rules/modsecurity_crs-plesk/rules/REQUEST-920-PROTOCOL-ENFORCEMENT.conf"] [line "810"] [id "920350"] [rev "2"] [msg "Host header is a numeric IP address"] [severity "WARNING"] [ver "OWASP_CRS/3.0.0"] [maturity "9"] [accuracy "9"] [tag "application-multi"] [tag "language-multi"] [tag "platform-multi"] [tag "attack-protocol"] [tag "OWASP_CRS/PROTOCOL_VIOLATION/IP_HOST"] [tag "WASCTC/WASC-21"] [tag "OWASP_TOP_10/A7"] [tag "PCI/6.5.10"] [hostname "SERVERNAME"] [uri "/plesk-site-preview/example.com"] [unique_id "17149707387469299914"]
Some elements (e.g. images) are missing or displayed as broken in Site preview in Plesk.

ModSecurity blocks access to Plesk Site Preview.

Disable the rule mentioned in the error message. In this example, with ID "920350".