Writable folder

Hi,

When I try to make a backup, I get the message that the folder “updraft” isn’t writable. I’ve tried to CHMOD it to 755, but this doesn’t work. Also 644 and 664 aren’t working. 777 is working, but that isn’t a very safe solution.

What are the correct permissions? Or do I need to contact my webhoster?

Thanks in advance

http://wordpress.org/extend/plugins/updraftplus/