I have edited functions.php file recently and also added a new folder to themes folder for custom endpoint and after that I wasn't able to login to wp-admin. I deleted the folder and code line from functions.php but it still doesn't let me to login. I have cleared all cache and cookies but still I get the same error :(
This mixed content error was visible earlier but I was able to login then.
P.S. I have recently changed wordpress domain name as well as home url and site url, also used search and replace tool to replace all old urls to new ones.
P.P.P.S. I have fixed mixed content error but the cookie error still occurs :(