Does 'buildozer android debug' generate an apk?
If no : set log_level = 2, run buildozer appclean, then buildozer android debug
If you don't understand the errors in the log post the FULL log file here as a .txt file
If yes: run the debug step, and look in the logcat file, search for 'traceback',
The cause of the issue will probably be in the lines following 'traceback'.
Do not send me your .py code.