server closed the connectio unexpectedly

Hi, I'm new in postgres, so I don't know alot, only the basics

I created a data base and create one user and when I want give privileges
this error apears

test_ip=# GRANT SELECT ON tb_allowed_ip TO zurron;
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!#

I'm running red hat 8.0, postgres version 7.2.2

thanks for any help