Two seemingly random errors appeared today, several times:
Cannot read property ‘tab’ of undefined’
Could not establish connection. Receiving end does not exist.
However, I believe I may have fixed it/worked around it in my scenario.
I am opening URLs from a CSV file in a new tab. Today, Kantu would error somewhere between the second and ninth URL.
Over the weekend the website changed its subdomain name and is now redirecting the old name to the new.
I searched/replaced the old name to the new in the CSV file and so far, no more errors.
I hope this may be of help to @admin and others.