Connection with DI SERVER SAP Business One

Hello everyone! I'm facing an issue with SAP B1 DI Server. I'm developing a webservice using wsdl references from DI Server. I referenced the wsdl files in my project and everything seems to work fine. But, when I try to connect to B1 I systematically get an error saying that I can't connect to Business One.

I've checked:

1.- Di Server License: I didn't have it, but asked for it and installed it.

2.- SBO DI Server: Up & Running

3.- TAO NT Service: Up & Running

What is most strange is that yesterday I tested the same code from my WS and it worked beautifully. Today when I try to perform another test it crashed. Any thoughts? Many Thanks! K.R