I changed line 127 of /usr/share/gwibber/plugins/twitter/gtk/twitter/__init__.py to use https instead of http which seemed to get through my work proxy:
http_url="https://api.twitter.com/oauth/access_token",
I changed line 127 of /usr/share/ gwibber/ plugins/ twitter/ gtk/twitter/ __init_ _.py to use https instead of http which seemed to get through my work proxy:
http_url="https:/ /api.twitter. com/oauth/ access_ token",