You run "docker ps -a" and see values in the PORTS column. You see values such as these for two separate containers:
Container 1 has this: 0.0.0.0:32775->5000/tcp
Container 2 has this: 5731/tcp
You cannot reach the containers that have no "->" symbol in them via web browsers or other network connectivity tools. You can reach those containers with the "->" symbol in the PORTS value. What is wrong with the Docker containers with only one TCP port and not "->" syntax?
Those containers with no "->" mapping symbol in the PORTS value in the results of a "docker ps -a" command were potentially created without a necessary flag. The "-P" option may be enough to get them to work properly.
For creating a container with a TCP port that will be exposed, use this command (with a known working Docker image):
docker create -it -P <image ID>
Alternatively you can use the "docker run" command to create and start a Docker container. Here is the syntax for doing that with a known good image to create a container with a TCP port that will be exposed:
docker run -d -P <image ID>