What happens to call on 5G SA if 404, 500 error code received?

Hello.

If there is error code 404, 500 for VoNR call, what happens to call on 5G SA?

Is it Fallback or not to LTE?

500 codes are server error in SIP.

404 Not Found.
The server has definitive information that the user does not exist at the domain specified in the Request-URI.
This status is also returned if the domain in the Request-URI does not match any of the domains handled by the recipient of the request.

More details here: SIP response status codes

Thanks!

So what will UE do?

Will it not retry for call?

I mean not like VoLTE retry for CSFB option with SIP error code.