Project export fails using the online compiler - receive message "Failed to export"

I having a working Mbed LPC1768 project. I cannot export this project using the online compiler. I tried many of the export toolchain options listed with no success. I get the same message “Failed to export.” I have tried both Windows 10/Linux using the Chrome browser. However, I can export some of my own legacy Mbed projects (circa 2012-2013) with the online compiler. And I experience no problems exporting these old projects to various toolchains including no problem creating ZIP archives.

One thing I have noticed is that projects that include the ‘mbed-os’ library will not export. Anyone else run into this situation?