Sharing between Macintosh and Windows
Your error is pointing you correctly to look at firewall and networking.

This should be fairly easy to narrow down with some facts:


If you don't have DNS - use IP addresses for all testing - fix the Mac and PC to specific IP
Ping works from Mac very reliably - you can use the network utility to ping by IP or host name.
Network Utility will also be useful to port scan the PC. You should be able to tell if the windows firewall is blocking your access 


My hunch since I run mongodb all the time on Mac and PC is your firewall would be likely blocking access. The only issues I never have is wrong IP, wrong port, firewall blocking, mongo configuration.

If you are comfortable on the command line - get mongodb on the Mac from https://brew.sh and then run brew install mongodb so you can connect from the command line and see explicit details on what errors happen.

$ mongo
MongoDB shell version v3.4.10
connecting to: mongodb://127.0.0.1:27017
2017-11-22T07:10:38.494-0600 W NETWORK  [thread1] Failed to connect to 127.0.0.1:27017, in(checking socket for error after poll), reason: Connection refused
2017-11-22T07:10:38.501-0600 E QUERY    [thread1] Error: couldn't connect to server 127.0.0.1:27017, connection attempt failed :
connect@src/mongo/shell/mongo.js:237:13
@(connect):1:6
exception: connect failed


So in your case, use the command line mongo to attempt a connection to your server at 10.0.1.9:27100