Sounds like an IP address conflict. Did you configure a static IP?
What happens is that ARP tables jump back and forth to the last known MAC (Media Access Control address, what WiFi/Ethernet use as a device identifier) that a packet from the IP address originated from. (*in some OSes, under typical/default conditions)
Check that your samba box doesn’t have the same IP address as something else on the network; sounds like they’re fighting over it.