error 400 on preview in admin

When I attempt to preview I get 400 error that says try using https.

When I insert the s in the address bar I can see the preview.

What do I need to tweak to get this to preview correctly all the time.

I have enabled SSL in the config files.

preview "what"?

Sounds like you've got wrong URLs or paths set in your admin configure.php file

Sorry. Was previewing product after modifying the product.

Clicking on preview sends me to http://productlistingpage. Then I get error 400. If I change the http to https then it will load the preview page properly.

I really think its a server issue. I had this problem once before due to some characters in the body of the item description. At that time I was using tab lite. But that was removed years ago and had been working fine for years.

this was the link that caused the error

http://www.mysite.com/mystore/admin/product.php?cPath=14_2&product_type=1&pID=2&action=new_product_preview&zenAdminID=2ob3o992u3sj30sctektfmctm3

ww.mysite.com being fictious name of course.

Server had Mod_Security active. After they shut it off everything worked fine.

Just as well, it made me start upgrading from 1.38a

mod_security will flag up certain keywords as security alerts ... so if you're using such words in your product descriptions, you may have to get them to relax the mod_security rules at least within your admin folder, or perhaps disable them altogether ... hopefully only from within your admin folder.