I've found that Network Wide Availability - Today or Network Wide Average Utilization - Today widgets do not show a chart but only linked image icon wich gives no chart at all as result, as shown below:

When I clicked on image then I got:

Then when tried to see any data - clicking on pointed buttons - my result was the error from website:

I submitted a case for that on CUstomer Portal. But I'm wondering if it is a bug in 2020.2.1 platform or anything else. I've tested that behaviour on evaluation instalation and got the same result. It is not critical (and widgets are very old) but why such widgets are available on the list to place on dashboard still if they won't work anymore?