Access front end as Admin but not Admin CP

[BaldNut]

Hi I wonder if anyone else has had this problem or can work out a resolve.

I have just completed upgrading from 4.2.2 to 5.1.5 and everything went great other than I cant login to admin cp.

My user is recognised as admin as I have all the admin options front end but when I try and login it does not let me.

Also, If I use wrong password it gives me a warning but if I use correct password it just reloads the login screen without notifying me of my login attempts.

I have checked my config and user id 1 is admin, I have checked my database user id is my admin account.

Please advise.

Kind regards.

[BaldNut]

Tried from another browser and was no problems.

[Mark.B]

Clear the browser cookies and cache, restart the browser.