Unable to get pgAdmin4 to connect to local database

I successfully added a connection to my production server (in the AWS cloud), but am having a problem connecting to my
localserver. When I try to connect, I get the error message box entitled “timeout” with the text “Connection to server
hasbeen lost”. 

The server is indeed running (in fact, I’m connected to it by pgAdmin3 as I get this message). Here are the connection
propertiesI’ve defined for the server: 
Host Name/Address    local:Port                    5432Maintenance Database    postgresUser Name            jackrgRole
                 SSL Mode            Prefer    (I also tried “Disable”) 

and here are the properties from pgAdmin3, which does successfully connect:
Host                    local:Port                    5432Maintenance DB        postgresUsername            jackrg

Note that the password is blank, I’m running OS X 10.11.6 and my local PostgreSQL server has the Version string
"PostgreSQL9.2.2 on x86_64-apple-darwin11.4.2, compiled by i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple
Inc.build 5658) (LLVM build 2336.9.00), 64-bit”.