Cannot Update Flash on my iMac

[Now is Tuesday, 5 September 2017, 1643  EDT.]

Here is my relevant information:

    •    Web browser and version  [Firefox v55.0.3]

    •    Flash Player version  [v26.0.0.151]

Here is my question, please:

Why can’t I update FlashPlayer?  I use an iMac, with a solid-state drive.   My connection to the Internet, works.  But when I try to update FlashPlayer, I see:

Unable to Check  /  There was a problem trying to check for available updates.  Check your Internet connection & try again.

Again, My connection to the Internet, works.  So I feel Lost.  😞  Please, help.  Thank you.