Modem manager problem on Slackware 15.0

On syslog of my Slackware 15.0 I see those annoying messages Oct 1 06:41:45 nas NetworkManager: [1696135305.0097] modem-manager: error poking ModemManager: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ExecFailed: Failed to execute program org.freedesktop.ModemManager1: Permission denied Oct 1 06:43:45 nas NetworkManager: [1696135425.0122] modem-manager: error poking ModemManager: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ExecFailed: Failed to execute program org.freedesktop.ModemManager1: Permission denied Oct 1 06:45:45 nas NetworkManager: [1696135545.0116] modem-manager: error poking ModemManager: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ExecFailed: Failed to execute program org.freedesktop.ModemManager1: Permission denied Oct 1 06:47:45 nas NetworkManager: [1696135665.0108] modem-manager: error poking ModemManager: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ExecFailed: Failed to execute program org.freedesktop.ModemManager1: Permission denied Oct 1 06:49:45 nas NetworkManager: [1696135785.0037] modem-manager: error poking ModemManager: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ExecFailed: Failed to execute program org.freedesktop.ModemManager1: Permission denied Oct 1 06:51:45 nas NetworkManager: [1696135905.0029] modem-manager: error poking ModemManager: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ExecFailed: Failed to execute program org.freedesktop.ModemManager1: Permission denied Oct 1 06:53:45 nas NetworkManager: [1696136025.0019] modem-manager: error poking ModemManager: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ExecFailed: Failed to execute program org.freedesktop.ModemManager1: Permission denied Oct 1 06:55:45 nas NetworkManager: [1696136145.0013] modem-manager: error poking ModemManager: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ExecFailed: Failed to execute program org.freedesktop.ModemManager1: Permission denied What to check? Thanks permissions are those: ls -lhd /usr/sbin/ModemManager -rwxr-xr-x 1 root root 1,8M nov 26 2021 /usr/sbin/ModemManager* Those are permission of serial device, I don't understand who change ttyS02 permissions ls -ld /dev/ttyS* crw-rw---- 1 root dialout 4, 64 ott 8 04:07 /dev/ttyS0 crw-rw---- 1 root dialout 4, 65 ott 8 04:07 /dev/ttyS1 crw--w---- 1 root tty 4, 66 ott 8 04:10 /dev/ttyS2 crw-rw---- 1 root dialout 4, 67 ott 8 04:07 /dev/ttyS3 grep -irl ttyS2 /etc /etc/default/grub~ /etc/default/grub /etc/radiusclient/port-id-map /etc/radiusclient/radiusclient.conf /etc/securetty /etc/serial.conf /etc/inittab~ /etc/inittab I have tried to set permissions as default (root:dialout and 660) to ttyS2 but... Oct 9 21:07:23 nas NetworkManager: [1696878443.0583] modem-manager: error poking ModemManager: GDBus.Error:org.freedesktop.DBus.Error.Spawn.ExecFailed: Failed to execute program org.freedesktop.ModemManager1: Permission denied