Login admin need rename everytime - problem

[HAAANZ]

Hi,

I have Prestashop 1.7.5.2.

I have some login address: for example www.xxx.cz/admin123. I can login just one time. When I try second time, I cant login. I must go tu FTP, change the name of admin folder, for example "admin1234". I can login with this new address www.xxx.cz/admin1234 but only one time and then same problem.

Somebody can help me?

Thanks

 

Hanz

[HAAANZ]

Thanks for answer. Yes, I know that. 

I rename it to something I want (for example admin123ABC). Then I can access to the back office with this url BUT JUST ONE TIME! 

When I log out and go second time to the back office, I cant login. I need change on FTP admin folder for another name and then I can login BUT JUST ONE TIME AGAIN.