Unable to access shares on laptop when it's connected via WiFi
Instead of using the Windows device name to access your share from other device, try first using the server's IP address. If that works, it tells you it may have something to do with your directory service. There could be another device having the same name, for example or the name is not propagated some how.
If SMB access via IP also does not work, try to telnet to your server's SMB TCP port 445 and see if it connects. If not, try starting some TCP service (say, Python HTTP Server) to isolate issue, it could still be a firewall issue.