Just adding some log file entries behind this, I cleared the log file, then restarted the service. Then attempted to play a video file on the android device.
root@truenas[~]# less /var/log/samba4/log.smbd
[2022/07/13 00:17:16.984582, 0] ../../source3/smbd/server.c:1734(main)
smbd version 4.15.7 started.
Copyright Andrew Tridgell and the Samba Team 1992-2021
[2022/07/13 00:17:16.987228, 1] ../../source3/profile/profile.c:55(set_profile_level)
INFO: Profiling turned OFF from pid 15133
[2022/07/13 00:17:17.072707, 1] ../../source3/smbd/files.c:809(file_init_global)
file_init_global: Information only: requested 462204 open files, 59392 are available.
[2022/07/13 00:17:19.802488, 3] ../../auth/auth_log.c:665(log_authentication_event_human_readable)
Auth: [SMB2,(null)] user [TRUENAS]\[smbmedia] at [Wed, 13 Jul 2022 00:17:19.802481 UTC] with [NTLMv2] status [NT_STATUS_OK] workstation [] remote host [ipv4:192.168.1.132:52426] became [TRUENAS]\[smbmedia] [S-1-5-21-2286527191-2304684957-3930965839-1005]. local host [ipv4:192.168.1.199:445]
[2022/07/13 00:17:19.803452, 4] ../../auth/auth_log.c:765(log_successful_authz_event_human_readable)
Successful AuthZ: [SMB2,NTLMSSP] user [TRUENAS]\[smbmedia] [S-1-5-21-2286527191-2304684957-3930965839-1005] at [Wed, 13 Jul 2022 00:17:19.803447 UTC] Remote host [ipv4:192.168.1.132:52426] local host [ipv4:192.168.1.199:445]
(END)