We are using civi 5.3 on Wordpress 4.9. Using CiviReports or CiviContribute, I am selecting Charts, and clicking the view button. The chart is not loading. I saw the other answers suggesting that I enable flash in chrome for this site, but this is happening on Chrome, Explorer and Safari. Could the paths for these graphs be wrong? Where would I check that? The charts have never worked for us, even before upgrading to 5.3.
Some browsers don't show up flash chart by default, you will need allow flash for certain urls or make it allow for all sites. This answer might be useful to fix your problem.