WWW-Authenticate header missing in response

[rahilwazir]

When I execute the following ruby bin/yg-export.rb, I get the following error

D, [2020-03-27T16:51:47.076552 #545451] DEBUG -- : MONGODB | Topology type 'unknown' initializing.
D, [2020-03-27T16:51:47.076659 #545451] DEBUG -- : MONGODB | Server 172.17.0.2:27017 initializing.
D, [2020-03-27T16:51:47.077974 #545451] DEBUG -- : MONGODB | Topology type 'unknown' changed to type 'single'.
D, [2020-03-27T16:51:47.078081 #545451] DEBUG -- : MONGODB | Server description for 172.17.0.2:27017 changed from 'unknown' to 'standalone'.
D, [2020-03-27T16:51:47.078129 #545451] DEBUG -- : MONGODB | There was a change in the members of the 'single' topology.
Logged in....
Traceback (most recent call last):
        5: from bin/yg-export.rb:15:in `<main>'
        4: from bin/yg-export.rb:15:in `new'
        3: from /home/rw/Downloads/yahoo-groups-export/lib/yahoo-group/group.rb:11:in `initialize'
        2: from /usr/share/gems/gems/mechanize-2.7.5/lib/mechanize.rb:464:in `get'
        1: from /usr/share/gems/gems/mechanize-2.7.5/lib/mechanize/http/agent.rb:317:in `fetch'
/usr/share/gems/gems/mechanize-2.7.5/lib/mechanize/http/agent.rb:737:in `response_authenticate': 401 => Net::HTTPUnauthorized for https://groups.yahoo.com/api/v1/groups/nzarchchat -- WWW-Authenticate header missing in response (Mechanize::UnauthorizedError)

Not really sure, if it's from the Yahoo API end or the Mechanize is malfunctioning.