Demo apps work but custom apps don't on EC2

Hi all -

I have shinyproxy running on an Amazon EC2 instance with ubuntu 16.04. I have everything set up and I can run the demo apps just fine so long as they are the default ones inside shinyproxy (hello, tabsets). When I try to run either a shiny app I wrote or Euler, I get the following error:

Caused by: com.spotify.docker.client.exceptions.DockerRequestException: Request error: POST http://localhost:2375/containers/create: 404, body: {"message":"No such image: niehaus/tariffimg:latest"}

My searching has shown that this is a relatively common error, so I have tried to troubleshoot it. As far as I can tell, everything should be working. I can run the docker image as so:

docker run -p 3839:3838 --rm niehaus/tariffimg

and it will say listening on '0.0.0.0:38383'. So all seems good as far as the image is concerned. What puzzles me is how shinyproxy can load the demo image openanalytics/shinyproxy-demo but not my app or euler openanalytics/.

I seem to have the docker server set up correctly as well to listen on the right port:

 docker.service - Docker Application Container Engine
   Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: e
  Drop-In: /etc/systemd/system/docker.service.d
           └─override.conf
   Active: active (running) since Tue 2019-04-23 00:38:33 UTC; 44min ago
     Docs: https://docs.docker.com
 Main PID: 2612 (dockerd)
    Tasks: 12
   CGroup: /system.slice/docker.service
           └─2612 /usr/bin/dockerd -H unix:// -D -H tcp://127.0.0.1:2375

Apr 23 01:05:38 ip-172-31-18-122 dockerd[2612]: time="2019-04-23T01:05:38.063424
Apr 23 01:05:38 ip-172-31-18-122 dockerd[2612]: time="2019-04-23T01:05:38.126864
Apr 23 01:05:38 ip-172-31-18-122 dockerd[2612]: time="2019-04-23T01:05:38.173687
Apr 23 01:05:38 ip-172-31-18-122 dockerd[2612]: time="2019-04-23T01:05:38.232382
Apr 23 01:05:38 ip-172-31-18-122 dockerd[2612]: time="2019-04-23T01:05:38.276452
Apr 23 01:05:38 ip-172-31-18-122 dockerd[2612]: time="2019-04-23T01:05:38.277607
Apr 23 01:05:38 ip-172-31-18-122 dockerd[2612]: time="2019-04-23T01:05:38.347431
Apr 23 01:05:38 ip-172-31-18-122 dockerd[2612]: time="2019-04-23T01:05:38.410794
Apr 23 01:12:56 ip-172-31-18-122 dockerd[2612]: time="2019-04-23T01:12:56.896670
Apr 23 01:12:56 ip-172-31-18-122 dockerd[2612]: time="2019-04-23T01:12:56.964667

and the docker image does exist:

REPOSITORY                      TAG                 IMAGE ID            CREATED             SIZE
niehaus/tariff                  latest              79312a979457        17 minutes ago      1.03GB
<none>                          <none>              22c104f49a9f        3 days ago          818MB
ubuntu                          latest              94e814e2efa8        6 weeks ago         88.9MB
openanalytics/r-base            latest              d75849af0fdb        2 months ago        576MB
openanalytics/shinyproxy-demo   latest              9a83d7d80ebf        2 months ago        925MB
hello-world                     latest              fce289e99eb9        3 months ago        1.84kB

At a loss for how to proceed so any suggestions are very welcome!

Solved my own problem here. Not quite sure how it originated, but I think it had to do with a docker config file in the wrong location.