Spotify authorization declined when providing username and password

[luciengaitskell]

When using the CLI with ./cspotcli -u <username> -p <password>, I consistently see

I main.cpp:195: Creating player
D Session.cpp:67: Connecting with AP <ap-gue1.spotify.com:4070>
D PlainConnection.cpp:101: Connected to spotify server
I Session.cpp:43: Received APHello response
D Session.cpp:48: Received shannon keys
E Session.cpp:95: Authorization declined
I PlainConnection.cpp:197: Closing socket...

I have tried both my email and provided username (found in Spotify account settings), along with ensuring my password does not contain any special characters.

Is this a known issue?

Thanks.