You may well have hit the nail on the head. Ryan, nayrk, the originator of this script, noted that you have to first enable access to their API server, for what reason I don’t know, but once done you can access it via this script too.
To enable access via IFTTT you will have to go to the IFTTT website, and create a free account. Once done you can search for a Blink applet, and try to set it up. Choose a simple one, and search for them by looking for ‘Blink’ applets for the USA, or ‘Blink Europe’ applets for if you are in Europe.
A simple one might be, “Get an email when Blink detects motion”. Having found this, at some point, as you follow through the steps, you will be asked to find a service which you want to link to this applet, and you will search for Blink. When you select Blink, it will ask you to log in. If there is a choice, I can’t recall, be sure to choose Blink Europe, if you are in Europe.
Once you select that service, you will be asked to authenticate yourself. Enter your Blink credentials, the same as you use to log into their app on your device. Once that goes through, you will be able to either arm or disarm that applet. Either way, IFTTT now have your credentials stored, so whenever you want to run that applet, it will use the credentials you entered. If you change them with Blink, the applet will no longer work, obviously.
Now that the Blink servers will accept your credentials, perhaps because it received them from an accepted/trusted source, IFTTT, you should now be able to log-in via the script, and it will no longer fall over at that point.
Send me a PM if you need further assistance.