Hi @Arnau_Cabrera ,
Welcome to Speckle! Feel free to Introduce yourself 
to the community if you want to! 
Please have a look at the following:
- Do you have Speckle Manager installed and an account added to it?
- Are you using the same account for both PCs? (If not is the project shared for both accounts?)
- Can you check if you have any firewall active and try to disable it? Or make sure your company’s IT is not blocking the connection.
Let me know how it goes.