Blog posts/pages links go to site home page-suddenly

https://www.mindtechnology.com/blog
(www.curiousmindnews.com redirects to the above link)
Using Atahualpa 3.4.9 theme
No admin changes made to the blog in 3+ months

I have not visited my blog to make a post in 2 months and today I found this has happened:
– When I click preview while creating a post it goes to my site’s home page. Also in Admin if I click the top left link to go to my blog it goes to the site’s home page.
– If you visit my blog and click any link for posts, pages, about, etc you will go to the site’s home page.

I have never had a problem with this site. Please point me in the right direction to solve this.

May or may not be related:
I have wpBackup installed. When I go to admin it shows my last 3 backups are recent. But if I go to wpBackup site it says the last backup was when I first installed it yet it all tests well.
(If this is not related then let me know and I’ll post this at the right place)