464 (No name)

Unofficial · AWS

An AWS Application Load Balancer received a request in a protocol its target group is not set up for, such as HTTP/1.1 for gRPC.

Class
4xx Client Error. The request has a fault, or cannot be met as sent.
Registered
No. AWS sends it, and it is not in the IANA registry, so other servers may mean something else by it.
References
AWS ALB

Every 4xx code

All HTTP status codes, in one table