cant add and or change pages of a uploaded chapter

hi,
i wanted to change the cover of my mangas first page because i finally have a cover with credits ready to credit all the artists that helped me. 
anyway  everytime i try to add a page to the chapter its in queue forever it wont load. i tried everything ereasing reuploading uploading not as first page moving it to first page later nothing worked.
Can you help me so i can change the covers of my chapters. My first chapter is currently without cover because of this and i dont want to loose all my views.