Your MediaServer’s IP address is no longer viable! And your Mac is looking to connect to it (which it really shouldn’t be)
So lets look at this from a different perspective…
Your internet router has an IP address assigned by your ISP (DHCP) I bet you your IP address lease via DHCP expired! Or, Your IP address was altered by the ISP as they needed to re-configure their network.
So why would this effect my MediaServer? Its on the inside non-routable address space I’ve setup 10.x.x. 172.x.x.x or 192.x.x.x. Your Media Server still leverages the Routers DHCP service to assign the IP address (non-routable) as well as the default route table. So you’ll need to restart your Internet Router and any WiFi AP’s you have and then lastly your devices that connect to your network so the IP addresses (if needed) as well as the route tables are reset.
Now you still have a second issue as your system is trying to connect to it for some reason. Once your’ve reset things the action that was pending should finish. But if it doesn’t you’ll need to try to figure out why your system is looking for your server. Do you have TimeMachine setup to backup on a schedule? Or have something that else needs updating.