Redmine

Hello,
I am using python 2.7.10 within Mac OSX 10.10.5 to perform some update operations within our Redmine tracking system.
The command:
redmine = Redmine('https://redmine.url', version= '3.1.0', username= 'purkayasthaa', password='#########')
throws no errors.
However when I try to print the name of the each project, thus:

projects = redmine.project.all()
for project in projects:
    print project.name

I get the error below:
redmine.packages.requests.exceptions.ConnectionError: HTTPSConnectionPool(host='redmine.url', port=443): Max retries exceeded with url: /projects.json?limit=100&offset=0 (Caused by NewConnectionError('<redmine.packages.requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x10ea13550>: Failed to establish a new connection: [Errno 8] nodename nor servname provided, or not known',))

It looks like the python Redmine library is having difficulties making a connection. Any pointers to resolve this will be appreciated.
Thanks
Anjan