DFU and nRF Toolbox Android Apps Won't Accept Zip Files for Firmware Developed under nRF Connect SDK

If I incorporate DFU with the appropriate prj.conf settings and the include files in the source according to devzone.nordicsemi.com/.../ncs-dfu, the build under nRF Connect 2.20 will generate dfu_application.zip and app_update.bin.  I noticed that same app_update.bin is in the zip file.  When I perform the DFU using the Device Manager app and the app_update.bin on my Motorola One Ace 5G Android 11 phone, the firmware update is successful.  However, when I use the DFU or nRF Toolbox app, selecting the Device Firmware Update service with dfu_application.zip, I get "Error: Invalid or too large file".  Based on the solution found here: devzone.nordicsemi.com/.../android-nrf-toolbox-dfu-can-t-load-zip-file, I've tried 3 different apps to select the file:  File Commander, File Manager+, and File Manager - XFolder, all of which are able to select the file, yet produce the same error.  When I load a zip file for code built from the nRF 5 SDK, it works fine.  Could you tell me if there's something else I need to do, or is there a problem with nRF Toolbox updating firmware built with nRF Connect 2.20 on an Android phone?
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