I can't start up a photo gallery on Word Press

My website is https://www.nkscouting.com

Over the past few years, I’ve started about 70 photo galleries, and this is the first time my Word Press hasn’t let me do so.

But now, I am unable to start another gallery. If I type in a word to start another photo gallery, and giving it the name
Caupain, it just gives me 3 error messages shown below:

Unable to create directory wp-content/gallery/caupain!
Directory wp-content/gallery/caupain is not writeable !
Unable to create directory wp-content/gallery/caupain/thumbs !

If anyone could help, I would appreciate it!