[Plugin: WP Super Cache] Server changed, cache disappeared.

Well, this is my problem :

1, I changed a server
2, I triggered the cache
3, The cache setting page told me that it was not working for the non-writable issues
4, I use chmod to make the changes
5, The cache setting page is okay (the .htaccess is even well modified by the cache), but then I just get this:

Cache contents

WP-Cache

* 0 cached pages
* 0 expired pages

WP-Super-Cache

* 0 cached pages
* 0 expired pages.

I use ssh to see, but found nothing in the /wp-content/cache

What’s the matter could possibly be?
Thanks in advance!