I cannot add a new email account even after following "help" page instructions.

I am trying to add a new email account. I am a programmer, and have been using thunderbird for a looonnnngggg time. Now it cannot do (add an account) what I have done many times before? I went to the "help" page, here: https://support.mozilla.org/en-US/kb/automatic-account-configuration. The "help" page says: "....add a new email account (using File > New > Existing Mail Account… or via the Account Settings)." Clicking on the "File > New > Existing Mail Account" and "File > New > Other Accounts" menu options do absolutely nothing! Also, doing this did absolutely nothing" "Another way to add a new account is to click on an existing account name (the displayed email address). Under the "Accounts" heading there are two options: "View settings for this account" and "Create a new account". Under "Create a new account", click "Email" to display the dialog box shown below." I am using 52.4.0 (64 bit). So, now what? Paul