Swagger UI and Docker Container Communication - api

Question

I have a docker container running Swagger UI on port 80 and I have another API running in another container on port 32788
http://127.0.0.1:80/ >>> returns swagger UI
http://127.0.0.1:32788/swagger.json >>> returns swagger API def
But when I put the json file into the Swagger UI field and hit explore, it says
NetworkError when attempting to fetch resource. http://127.0.0.1:32788/swagger.json
Any ideas on how to solve this. The docs say that they should automatically be connected to the bridge network.
Below is the result of the network inspection
docker network inspect bridge
[
{
"Name": "bridge",
"Id": "4b5cc1526055297df70dc9adc4959fcee93384c412fbf90500c041b5b83ed43a",
"Created": "2018-01-17T03:48:39.2325461Z",
"Scope": "local",
"Driver": "bridge",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "172.17.0.0/16",
"Gateway": "172.17.0.1"
}
]
},
"Internal": false,
"Attachable": false,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {
"257a15af9ab9b25c6c5622fb0ebe599e5703b2ca5f2e4eaa97a8745a21e7f9a9": {
"Name": "pensive_neumann",
"EndpointID": "22be4b781f75e071bcb0098b917b81b16ca493e9080848188dd7a811c27070ec",
"MacAddress": "02:42:ac:11:00:02",
"IPv4Address": "172.17.0.2/16",
"IPv6Address": ""
},
"30de904a599a19075d5e20ef5d974a11be9d7e58a68d984a24f4af9e22c4d92b": {
"Name": "naughty_mirzakhani",
"EndpointID": "f704b3e103a82ca5c56d5955ac27845d8951cfe13f0bc3e1ccc8717ea9c28d39",
"MacAddress": "02:42:ac:11:00:03",
"IPv4Address": "172.17.0.3/16",
"IPv6Address": ""
}
},
"Options": {
"com.docker.network.bridge.default_bridge": "true",
"com.docker.network.bridge.enable_icc": "true",
"com.docker.network.bridge.enable_ip_masquerade": "true",
"com.docker.network.bridge.host_binding_ipv4": "0.0.0.0",
"com.docker.network.bridge.name": "docker0",
"com.docker.network.driver.mtu": "1500"
},
"Labels": {}
}
]
Edit to explain how started each:
The API is part of Azure Machine Learning so its hard to say how it gets started exactly (unless there is some command I can run in docker):
az ml service create realtime
Swagger UI was started as follows:
docker run -p 80:8080 swaggerapi/swagger-ui