OTP not always presented as expected

[shiren00]

• Run on Command Prompt on Win10 64bit
• nndownload Binaries v1.12.2 for Windows
• Input nndownload_v1_12_2.exe --username "xxx" --password "xxx" https://www.nicovideo.jp/watch/sm9

Logging in...
Traceback (most recent call last):
  File "nndownload\nndownload.py", line 1819, in main
  File "nndownload\nndownload.py", line 1686, in login
IndexError: list index out of range
Traceback (most recent call last):
  File "nndownload\nndownload.py", line 1853, in <module>
  File "nndownload\nndownload.py", line 1819, in main
  File "nndownload\nndownload.py", line 1686, in login
IndexError: list index out of range
[1724] Failed to execute script 'nndownload' due to unhandled exception!

[shiren00]

• I have not set two-factor authentication on my account.

[AlexAplin]

The OTP code is presented regardless of whether two factor is enabled on the account.

• Do you see anything like this when you login from your browser, or do you go straight to the home page and show as logged in?
• Does the same thing happen if you try a different browser (Firefox, Chrome, Edge)?
• Do you see any "saved" (trusted) devices on this page? https://account.nicovideo.jp/my/history/login

[shiren00]

In the first place, the browser (= OTP code?) does not appear. The python error message only.

Do you see any "saved" (trusted) devices on this page? https://account.nicovideo.jp/my/history/login

I looked at the page, the login itself seems to be been. It is contained in "valid access"(現在のアクセス) and "Login History"(ログイン履歴).