How to Mount a Samba Share on Ubuntu 20.04 server for Raspberry Pi 4/400

I have been trying very hard to mount a samba share. The following works well in all x86-based Ubuntu 20.04. But it fails to mount in Raspberry Pi based Ubuntu 20.04.

//192.168.1.5/Media /mnt/smb cifs guest,_netdev,uid=ronny 0 0

It appears /etc/fstab is different too between the two platforms. Would this be the reason?

on x86:

UUID=a1e8f10b-a17d-49ef-aa65-1862db39786f / ext4 defaults 0 0/swap.img       none    swap    sw      0       0//192.168.1.5/Media /mnt/smb cifs guest,_netdev,uid=ronny 0 0

on RaspPi:

LABEL=writable  /        ext4   defaults        0 1LABEL=system-boot       /boot/firmware  vfat    defaults        0       1//192.168.1.5/Media /mnt/smb cifs guest,_netdev,uid=ronny 0 0

I hope someone can show me the way out of this darkness.

Update:

Whe I run sudo mount -a, it mounts successfully. It's when the Raspberry Pi is rebooted/started is when it failed to mount. here's what's on /var/log/syslog:

Sep 12 21:01:05 containers2 systemd[1]: Mounting /mnt/smb...Sep 12 21:01:05 containers2 systemd[1]: mnt-smb.mount: Mount process exited, code=exited, status=32/n/aSep 12 21:01:05 containers2 systemd[1]: mnt-smb.mount: Failed with result 'exit-code'.Sep 12 21:01:05 containers2 systemd[1]: Failed to mount /mnt/smb.