For Tridion Sites 9.0, when publishing large files this fails with error "cause: HTTP/1.1 413 Request Entity Too Large "

- When publishing large pages, this fails with error below

BaseHTTPSTransportConnector - Unable to send TransportPackage <TCMID>.Content.zip to url: https://HOSTNAME/httpupload cause: HTTP/1.1 413 Request Entity Too Large

- No errors are seen in the Tridion or Application Windows event logs on CM server.
- No errors seen in the Deployer log file, verified that the package never reaches the Deployer.
- Deployer application.properties file in config folder has large file uploads enabled, as discussed in KB article Deployer microservice fails with error "Request Entity Too Large" just in case.

spring.http.multipart.max-file-size=1000Mb
spring.http.multipart.max-request-size=1000Mb

- Issue is seen in UAT environment, but not in Development environment.
- In UAT environment, customer has a Nginx server acting as load balancer in CM and CD environments.

Issue resolved after Nginx default file upload limit was increased, as discussed in below blog post for param Client_max_body_size.
https://www.tecmint.com/limit-file-upload-size-in-nginx/

Only the Deployer endpoint path needed to be increased, such as

https://HOSTNAME/DEPLOYER_SERVICE/httpupload