The default settings provided in voicemail.conf.sample trigger a warning: https://github.com/asterisk/asterisk/blob/master/configs/samples/voicemail.conf.sample#L56
WARNING[37220]: app_voicemail.c:14658 actual_load_config: maxsilence should be less than minsecs or you may get empty messages
These settings should be adjusted so they don't trigger that, to reduce the amount of warnings on new installs.
You must be