I have observed that Owncloud V 10.9.1 is not creating .htaccess file.
So, this error is coming.
You need to go to file manager of public_html or owncloud main folder/root folder.
Click on right side top gear button / setting button.
click on Show Hidden files.
Create new file named .htaccess
if it is already exists, do not over write.
just add following line and save.
RewriteRule .* – [E=HTTP_AUTHORIZATION:%{HTTP:Authorization},L]
your problem is resolved now.
