Have to reset password every time I log in

I have recently noticed that I have to reset the password every time I need to log into my wordpress site. I have tried adding a new user and the problem is still there, also tried re-uploading all of the wordpress admin files.

When I enter the wrong user details I get the ‘wrong password’ message but when I enter the correct details and click log in the page refreshes but without the login information filled in, no mention of incorrect password. If I reset the password it logs in fine until the next time where the problem replicates.

Hope someone can help!