[Serusers] Server does not see the REGISTER message

[Sandra]

Hello, 
 
I have a problem with SER. The server starts successfully: 
 
 
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 
Mar  3 12:14:11 localhost ser: WARNING: could not rev. resolve 159.199.75.160  
Mar  3 12:14:11 localhost ser: Listening on  
Mar  3 12:14:11 localhost ser:               127.0.0.1 [127.0.0.1]:5060 
Mar  3 12:14:11 localhost ser:               159.199.75.160 
[159.199.75.160]:5060 
Mar  3 12:14:11 localhost ser: Aliases: localhost:5060 
localhost.localdomain:5060  
Mar  3 12:14:11 localhost ser: Listening on  
Mar  3 12:14:11 localhost ser:               127.0.0.1 [127.0.0.1]:5060 
Mar  3 12:14:11 localhost ser:               159.199.75.160 
[159.199.75.160]:5060 
Mar  3 12:14:11 localhost ser: Aliases: localhost:5060 
localhost.localdomain:5060  
Mar  3 12:14:11 localhost ser: Listening on  
Mar  3 12:14:11 localhost ser:               127.0.0.1 [127.0.0.1]:5060 
Mar  3 12:14:11 localhost ser:               159.199.75.160 
[159.199.75.160]:5060 
Mar  3 12:14:11 localhost ser: Aliases: localhost:5060 
localhost.localdomain:5060  
Mar  3 12:14:11 localhost ser: Iniciación de ser succeeded 
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 
 
But when I send him a REGISTER message, the server do nothing. 
My SIP_DOMAIN=localhost, and the REGISTER message arrives to the PC where the 
server is running. 
 
I have not changed the ser.cfg which becomes with the installation. 
Can anybody help me?