Problem with start data registration form

Hi, Greetings, I have installed GRAV and then accessed the installation folder
When accessing this address, a registration form is presented that requires account data, data that I proceed to register in the form. Once filled, I click on “Create User”, but a response is generated again with a blank form, that is, without giving way to the login page, I have verified that the folders have permission 0755 and the files 0644
but despite this I have the impression that the data is not saved, since as I commented previously, the blank form is displayed again,

thanks for your help