If you are in the practice of deleting pages and then creating a 301 redirect from the deleted page to a different page, be aware of the following. You cannot create a redirect for a deleted page, when that page is still in the recycle bin. 

Consider this example. You have a page with a URL of /so-long-summer and another page with a URL of /hello-autumn. You want to delete /so-long-summer and redirect that URL to /hello-autumn. When you delete /so-long-summer it is placed in the recycle bin for 30 days. You cannot create a redirect tor /so-long-summer, because it is still a valid URL; it is just inaccessible. 

In this instance what you should do is first rename /so-long-summer so that it has a different URL when it goes into the recycle bin. The process goes like this:

1. Rename /so-long-summer to /so-long-summer-deleted.
2. Delete /so-long-summer-deleted. This sends it to the recycle bin.
3. Create a 301 redirect from /so-long-summer to /hello-autumn.

If you decide, before the 30 days are up, to restore /so-long-summer, you can do this:

1. Delete the 301 redirect from /so-long-summer to /hello-autumn.
2. Restore /so-long-summer-deleted from the recycle bin.
3. Rename /so-long-summer-deleted to /so-long-summer.