When exploring the C1_W1_lab04 “Optional Lab: Cost Function”, I simply ran the cell code, which is supposed to output an interactive plot. But the actual output is just as the following pictures – no plot, only text.
Hey @Yulin_Li,
Welcome to the community. Many learners seem to be facing an issue regarding the interactive widgets in the labs. Hey @chris.favila, can you please let us know why is this happening? Is it anyhow related to the Internet connectivity or the load on Coursera servers or the browser on which the labs are running? Thanks in advance.
Cheers,
Elemento
@Yulin_Li, are you running the code in your browser from the Coursera Lab, or are you running on some other platform?
Hey @TMosh and @Elemento , thanks a lot for your reply.
I’m running the code in my Chrome browser from the Coursera Lab, not other platforms.
Thanks for your report. I’m using Chrome also, and it seems to work as intended for me.
The only “interactive” thing about that plot is that you can modify the ‘w’ slider, and if you wait a few 10’s of seconds, you’ll see a new plot that uses the new ‘w’ value.
The plot can be extremely slow to update, depending on your internet connection and how busy Coursera’s servers are.
However, I noticed you have raw text shown for the Canvas toolbar. Those should be icons, not plain text. Try disabling any pop-up blockers that you may have active. They may be blocking the interactive tools.
The figure and toolbar should look like this:
Tip: Use a browser incognito mode with popup blockers disabled.
Thanks, @TMosh , for all of your detailed replies.
I’ve tried to disable my pop-up blockers in Chrome, and I found there was no active pop-up blockers blocking the interactive tools. So I guessed it maybe the result of bad network. Then, I tried to change my network environment by some VPN applications, and kept waiting for response for a long time. But unfortunately, It still didn’t work.
Then, I downloaded the lab files to run it in my own jupyter notebooks, and that finally worked. Since I still opened the lab files in my Chrome browser, I guess for me, the cause of this problem is not the browser blocker settings.
I just go back here and read your latest reply today, so I tried again, just using the Chrome browser and Cousera online lab. Surprisingly, the image can now be displayed normally!
I don’t know if the maintainers have done some work to fix this problem, but I’m very glad to see this finally works perfectly. Thanks for your efforts！ 
Sometimes the cause is with your browser cache or bad cookies.
