Got "KeyError: 'request_token_key' " upon first login and OAuth

[skierpage]

I read about video2commons in [Help:Converting video])https://commons.wikimedia.org/wiki/Help:Converting_video). I went to https://iw.toolforge.org/video2commons , I got a green button prompting me to login to Commons, I did so; I think that prompted me to do a central login, I did so; I got an OAuth authorization dialog for video2commons, which I approved, then
https://video2commons.toolforge.org/oauthcallback?oauth_verifier=dd0e2a4c1318b0a5dce602ed2ee1d5c8&oauth_token=bb882e65c9deb55b50a0418026242c67

displayed the following error (I split the lines, they were all mashed together in the pink error box.)

Please file an issue in GitHub: Traceback (most recent call last):
File "/data/project/video2commons/www/python/venv/lib/python3.11/site-packages/flask/app.py", line 917, in full_dispatch_request rv = self.dispatch_request() ^^^^^^^^^^^^^^^^^^^^^^^
File "/data/project/video2commons/www/python/venv/lib/python3.11/site-packages/flask/app.py", line 902, in dispatch_request return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args) # type: ignore[no-any-return] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/data/project/video2commons/www/python/src/../../../video2commons/frontend/app.py", line 217, in logincallback session['request_token_key'], ~~~~~~~^^^^^^^^^^^^^^^^^^^^^
KeyError: 'request_token_key' 

so here I am filing an issue.

I returned to https://iw.toolforge.org/video2commons , it again prompted me to login with the green button; this time it went straight to an OAuth page , again I allowed, and then video2commons.toolforge.org displayed "Your tasks" and let me get to work.