Hello @eder, welcome to the Let's Encrypt community. 
Standalone is one of the hardest to debug since Certbot spins up a temporary server to service the ACME HTTP-01 challenge and then stops the temporary server. Thus it is very transitory.
The online tool Let's Debug can be of assistance while the temporary server is running to serving the ACME Challenge.
Certbot is not a recommended ACME Client for Windows.
Here is a list of some of the ACME Clients ACME Client Implementations - Let's Encrypt