I think I messed up. In the project I'm working on I made a Module adding some PageLayouts to the Masterpages and Page layouts library through it. After deploying the solution the Masterpages and Page layouts now fails. When I click the link in Site Settings, it fails. But if I write the url straight into the URL bar in my browsers, it shows it perfectly.
One of my PageLayouts was named Default.aspx. First I thought that I might had overwritten one of the existing neccesary pagelayout files with that, but as I looked through all my other websites, non of them had Default.aspx, only DefaultLayout.aspx.
I have no idea of why else this happened. My guess is that it's the Redirect.aspx page which is failing hard, but I have literally no idea of why this happened.
Has anyone faced this issue beforehand? I couldn't find anything on google or other search engines.