On one of three machines, Thunderbird Linux password manager does not work; Windows 10 does

I have several machines that dual-boot Windows 10 and Linux openSUSE Leap 15.0. Thunderbird is installed on all machines for both operating systems. The two Thunderbirds both access the same profile on each machine. On all but one machine, Thunderbird works correctly in both operating systems. On the machine I most recently set up, Thunderbird works fine in Windows 10, but password manager is broken in openSUSE. Linux Thunderbird is 60.3.0 (64-bit).

In the faulty Thunderbird, all messages and address book are same as in Windows, but clicking Edit -> Preferences -> Security tab -> Saved passwords pops up a window with no entries. In Windows, doing Tools -> Options -> Security tab -> Saved passwords pops up a window with a list of a number of accounts with saved passwords.

In the Linux Thunderbird, trying to get messages brings up a password request box. When I type the password and do NOT check the remember password box, Thunderbird connects to the server and downloads new mail. In the password request box, if I type the password and DO check the remember password box, nothing happens: no connection, no mail, no remembered password.

I have compared all the Thunderbird settings on the faulty box with the settings on the machines that work right, and everything looks the same.

A similar issue was posted at https://support.mozilla.org/en-US/questions/1234460, but there is no solution there.

What can I do to get the openSUSE Thunderbird password manager working on this one machine, like it does on the others?

Thanks, Howard