You probably already have this in your script, but I found that I needed the following in my services-start script on my AX86 Pro to get Win 10 shares to work:BTW... when creating a Windows share... you can add the "Everyone" group to the share name... give it read/write access. Then it doesn't need a password. Or you can just use "admin / admin" in that case. But please know... that's the "I'm going to leave the door unlocked and wide-open" insecure approach of doing things, but if you don't have curious users on your network on a mission to destroy your backups in unsecured backup folders like this, it's a good start... then start experimenting with locking things down with usernames/passwords after you get this working.
Please be sure to share a screenshot your configuration screen or /jffs/addons/backupmon.d/backupmon.cfg file, to make sure everything looks right... happy to help!
Bash:
#!/bin/sh
/sbin/modprobe md4