GCP Registry behind HAProxy not working properly

Help!
1

I have configured my GCP docker registry using HA Proxy. Here is my HA Proxy configuration.

frontend myfrontend
  bind 0.0.0.0:8080
  use_backend maven-repo if { path_beg -i /repository }
  use_backend gcp-repo if { path_beg -i /v2/dev-registry }

backend maven-repo
  server maven-repo mvn01-ashok-dev.net:443 ssl verify none check inter 5s

backend gcp-repo
  server gcp-repo dev-docker.pkg.dev:443 ssl verify none check inter 5s

While pulling docker image from through HA Proxy, i am getting following error.

ashok@ubuntu:~$ docker pull localhost:8080/dev-registry/gateway-cluster-images/nextgen-nativebridge:1.1.0
Error response from daemon: error parsing HTTP 404 response body: invalid character '<' looking for beginning of value: "<!DOCTYPE html>\n<html lang=en>\n  <meta charset=utf-8>\n  <meta name=viewport content=\"initial-scale=1, minimum-scale=1, width=device-width\">\n  <title>Error 404 (Not Found)!!1</title>\n  <style>\n    *{margin:0;padding:0}html,code{font:15px/22px arial,sans-serif}html{background:#fff;color:#222;padding:15px}body{margin:7% auto 0;max-width:390px;min-height:180px;padding:30px 0 15px}* > body{background:url(//www.google.com/images/errors/robot.png) 100% 5px no-repeat;padding-right:205px}p{margin:11px 0 22px;overflow:hidden}ins{color:#777;text-decoration:none}a img{border:0}@media screen and (max-width:772px){body{background:none;margin-top:0;max-width:none;padding-right:0}}#logo{background:url(//www.google.com/images/branding/googlelogo/1x/googlelogo_color_150x54dp.png) no-repeat;margin-left:-5px}@media only screen and (min-resolution:192dpi){#logo{background:url(//www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png) no-repeat 0% 0%/100% 100%;-moz-border-image:url(//www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png) 0}}@media only screen and (-webkit-min-device-pixel-ratio:2){#logo{background:url(//www.google.com/images/branding/googlelogo/2x/googlelogo_color_150x54dp.png) no-repeat;-webkit-background-size:100% 100%}}#logo{display:inline-block;height:54px;width:150px}\n  </style>\n  <a href=//www.google.com/><span id=logo aria-label=Google></span></a>\n  <p><b>404.</b> <ins>That’s an error.</ins>\n  <p>The requested URL <code>/v2/dev-registry/gateway-cluster-images/nextgen-nativebridge:1.1.0</code> was not found on this server.  <ins>That’s all we know.</ins>\n"

When I hit the URL in the browser I am getting the following response.
URL: dev-docker.pkg.dev/v2/dev-registry/gateway-cluster-images/nextgen-nativebridge:1.1.0

{
   "mediaType": "application/vnd.docker.distribution.manifest.list.v2+json",
   "schemaVersion": 2,
   "manifests": [
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "digest": "sha256:3aee49a3c67bb0955033928b3a7b06aa77b9b0cd017a4516d0eab6a14c2001e1",
         "size": 2192,
         "platform": {
            "architecture": "amd64",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
         "digest": "sha256:8ed08295f67053a08ecf4bc74adc24da4261dce0f18cbc8be4902e7c555f9dfc",
         "size": 2192,
         "platform": {
            "architecture": "arm64",
            "os": "linux"
         }
      }
   ]
}