Login bugs

Hi!

I have a login problem – when students want to login into their account, sometimes (not always) after clicking the “sign in” button it doesn’t redirect to the student dashboard, but it shows an empty red rectangle or the login page as it was before, some students also told me that it showed that they had an incorrect password, but other times their password worked. It works after refreshing the page – it will redirect me to the student dashboard but it looks quite unprofessional so I’m looking for a better solution.

I’m sending a screenshot:

https://drive.google.com/file/d/1UpPJnoLjK9ThuyWqltu22mmMtJSxl4Rz/view?usp=sharing

Thanks for helping me sort this.

The page I need help with: [log in to see the link]