Well, typically 404s indicate the requested resource cannot be found. Either the requested details are wrong or they have not been loaded/removed. To get started please follow our troubleshooting guide here
Can you share the gateway logs for pod with the issue? You may first want to follow the link above.
Can you monitor or check that the pod/gateway has loaded all the APIs? The link has a section that mentions this
Considering the gateways use a shared directory, you may want to ensure you only write to one gateway when updating APIs to avoid double-writing or overwriting.
Sorry, I don’t know what this means
The link shared is a very good place to start. Please note that the 404s could be coming from the gateway or even your upstream URL. The gateway logs would indicate