Nikecow said:
For anyone interested, I fixed this by setting the samba protocol to 3 which Windows 10 apparently uses.

"server max protocol = SMB3"

I also had to give the samba user a samba password on the server with "smbpasswd <username>"
Actually it is the Guest browsing restrictions that Microsoft implemented, not SMB. There is an updated guide from the beginning of March that explains it, how to get Windows to see Linux shares.

See this from last year. It still works. Windows 10: Unable to Connect to Samba Shares schkerke.com