I run my .py program many times, it always worked.
But now that I have a new internet service provider with a different router
(which I port forwarded) the same program does NOT run. My program is a web
server it uses this line:
return render_template('main.html', **templateData)
I always get the following error:
BTW, I am using a new Raspberrypi 3 B+. I do not believe
that it is the problem.
Please help me. Thanks