The MyBB Requirements check failed due to the reasons below. MyBB installation cannot continue because you did not meet the MyBB requirements. Please correct the errors below and try again:
The cache directory (cache/) is not writable. Please adjust the chmod permissions to allow it to be written to.
The uploads directory (uploads/) is not writable. Please adjust the chmod permissions to allow it to be written to.
The avatars directory (uploads/avatars/) is not writable. Please adjust the chmod permissions to allow it to be written to.
You can CHMOD those folder either from the cPanel File Manager or by using a FTP client like Filezilla or SmartFTP.
CHMODing the folders to 755 should work, if not try 777.
