[CentOS] OT: Problems with NextCloud 13.0.1 under Centos7

Hi all,

 I have a strange problem with a clean NextCloud 13.0.1 install under
CentOS 7 (fully patched): when I try to login with admin user immediately
after setup, returns to login page without returning any error.

 An no errors in nginx or php log files ...

 I am using the following components:

 rh-php71
 rh-mariadb102
 nginx 1.12

 Any idea?

Many thanks.