This is the Prestashop admin login loop.
Unfortunately there is no standard solution for it. I have been in it too a few times. Fortunately after sometime I got out - wondering what I had done different.
You can search the internet for "Prestashop admin login loop" for suggestions.
A few of the options that you can try are:
- empty the cache (can be done with Prestools without entering the backoffice).
- delete .htaccess
- try another browser/computer
- use https instead of http (
- disable apache mod security
- use localhost instead of 127.0.0.1
- disable the option "Check the IP address on the cookie" in preferences
- check that you have the right settings in the ps_shop_url table
- change settings in the ps_configuration_table: PS_COOKIE_LIFETIME_BO=480; PS_COOKIE_CHECKIP= 0
- Changed "PS_CIPHER_ALGORITHM" from 1 to 0.