This message means that the locally configured internal limit was been exceeded in modsecurity. This limit is used to prevent a special type of DOS attack on the WAF itself. This is not caused by any of the Atomicorp rules. If you are using third party rules, please contact the rules developers for assistance.
When using just the Atomicorp rules, this error is caused by the following settings:
SecPcreMatchLimit
SecPcreMatchLimitRecursion
They limit the degree to which modsecurity will inspect content. This error means that modsecurity has stopped inspecting the content because the content itself has exceeded these limits. If your system is generating these kinds of errors, generally just need to increase the limits higher on your system as explained below.
It is also possible this is occurring due to an actual DOS attack on your system. If you are certain this is not a DOS attack, simply increase these limits accordingly for your system. We recommend a minimum of 250000 for a modern system, then restart your web server.
SecPcreMatchLimit 250000 SecPcreMatchLimitRecursion 250000
You may have to increase these limits for your system if you continue to get PCRE limit errors. If you have increased the limits, and are still experiencing these errors, please open a ticket with support and we can help you investigate this issue.