Portainer host is connected to 3 endpoints via the agent.
Only 1 endpoint is giving an error “Unable to retrieve volumes”, the remaining 2 and local endpoint work. All other functions work.
Error from Portainer logs = “2020/09/03 15:39:38 http: proxy error: missing identifier in Docker resource list response”
I proceeded to upgrade the portainer-agent to the latest API 2.0 version, which did not have any affect.
I deployed a new portainer-ce container which does not have /data mapped so we can excluded any database errors. I added the endpoint and still received the same error.
I deployed a portainer 1.24.1 container again without /data mapped and added the endpoint and I can see the volumes.
Due to the above this appears to be specific to portainer-ce and I am happy to provide further information for troubleshooting. Docker version of problematic host is 1.13.1 where all my other hosts are running much newer versions 19.03. RHEL 3.10.0-1127.13.1.el7.x86_64