Dockerized DCTM 7.3 and Dockerized DCTM REST 7.3 not able to retrieve global registry or its documents - documentum

Question

My setup consists of
Documentum Content Server 7.3 (dctm-cs) running in a docker container (from EMC)
Documentum REST Services 7.3 (dctm-rest) running in a docker container (from EMC)
I am definitively able to get information from within dctm by running queries against it with iapi, for example:
API> ?,c,select user_name from dm_user enable (return_top 5)
user_name
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
docu
ubuntudb
dm_superusers
dm_superusers_dynamic
dm_browse_all
(5 rows affected)
I am also able to $ curl http://localhost:8080/dctm-rest/repositories.json from both the dctm-rest container as well as its host container and get the results:
{"id":"http://localhost:8080/dctm-rest/repositories","title":"Repositories","author":[{"name":"EMC Documentum"}],"updated":"2017-08-16T21:42:44.177+00:00","page":1,"items-per-page":1000,"total":1,"links":[{"rel":"self","href":"http://localhost:8080/dctm-rest/repositories.json"}],"entries":[{"id":"http://localhost:8080/dctm-rest/repositories/ubuntudb","title":"ubuntudb","summary":"ubuntudb","updated":"2017-08-16T21:42:44.178+00:00","published":"2017-08-16T21:42:44.178+00:00","links":[{"rel":"edit","href":"http://localhost:8080/dctm-rest/repositories/ubuntudb.json"}],"content":{"type":"application/json","src":"http://localhost:8080/dctm-rest/repositories/ubuntudb.json"}}]}
Attempting to $ curl http://localhost:8080/dctm-rest/repositories/ubuntudb.json, however hangs indefinitely.
I have attempted to provide the default username and password via basic HTTP authentication, also with the same results.
The contents of the dfc.properties file in dctm-cs:
dfc.data.dir=/opt/dctm
dfc.tokenstorage.dir=/opt/dctm/apptoken
dfc.tokenstorage.enable=false
dfc.docbroker.host[0]=ubuntustateless
dfc.docbroker.port[0]=1489
dfc.crypto.repository=ubuntudb
dfc.session.secure_connect_default=try_secure_first
dfc.globalregistry.repository=ubuntudb
dfc.globalregistry.username=dm_bof_registry
dfc.globalregistry.password=AAAAEL9wp8c6k3K2UTQJwTYO5kMnE3rDrHJVDL+LijAg+zLk
The contents of the dfc.properties file in dctm-rest:
dfc.docbroker.host[0]=172.18.0.1
dfc.docbroker.port[0]=1489
#Add the global registry repository name to the following key.
dfc.globalregistry.repository=ubuntudb
#Add the username of the global registry user to the following key.
dfc.globalregistry.username=dmadmin
#Add an encrypted password value for the following key.
dfc.globalregistry.password=password
dfc.exception.include_id=false
dfc.exception.include_decoration=false
I have attempted to change the value of dfc.globalregistry.username to be the same as in dctm-cs, to no avail and same hang on request.
I have also attempted to use both encrypted and decrypted values for dfc.globalregistry.password, in both dctm-cs and dctm-rest also with no luck.