ADC might be crashed if preauthentication policies of Gateway are used.

Please use nFactor authentication.
If ADC is crashed on a supported version, please open a technical support case and provide a core dump for the investigation.

nFactor authentication
https://docs.citrix.com/en-us/citrix-adc/current-release/aaa-tm/authentication-methods/multi-factor-nfactor-authentication.html

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Problem Cause

It’s a known issue. Authentication, authorization, and auditing preauthentication policies (Classic AAA Pre-authentication policy) are deprecated from NetScaler 12.0 build 56.20 onwards and as an alternative. Classic Gateway and AAA policies will continue to remain available with no changes to existing functionality until Q2 2023. Citrix recommends that you move to Advanced policies which has enhanced features and functionalities.

Preauthentication policies and profiles
https://docs.citrix.com/en-us/citrix-gateway/current-release/vpn-user-config/endpoint-policies/preauthentication-policies-and-profiles.html

Notice of Status Change Announcement for Citrix ADC (Formerly NetScaler ADC) Classic Policy Based Features and Functionalities
https://support.citrix.com/article/CTX296948