I just did this again yesterday. I had no problems but I did have to log in as usual. Considering that I have about half a dozen google sheets with this code it may take a bit when doing it the first time. I remember when I did it for the very first time I had to futz with it. Meaning saving, deploying, hitting the test button over and over again until it just worked. One time I also had to switch the Webhook from Webform to JSON and then back to Webform. I would give it a few hours then try it again.
I know this sounds repetitive but you could try a new sheet and follow the instructions over again. Just to make sure there was not a missed step. New Sheet, New Script, New Webhook. Do it all over again. Once you get it you will be all set.