Paged Navigation not working

I’ve been trying to sort out problem with Permalinks going to Error 404 page. I’ve gone through suggestions of generating rewrite rules in Settings>Permalinks; checking permissions on .htaccess file; and deactivating and deleting plugins. I then went through all the permalinks to my posts and made sure they conformed to a single format, the default format. All to no avail.

I then had a closer look at http://codex.wordpress.org/Using_Permalinks and at the bottom of the page – under Paged Navigation Doesn’t Work (which seems to be my problem) – I tried the solutions suggested, deleting contents from .htaccess file, generating new rewrite rules, deleting .htaccess file and uploading a new file, with permissions changed to 666. None of this works.

Apart from in default, Page Navigation Permalinks go to 404 Error page.

The codex page says that if none of above works, then to look at this support question – http://wordpress.org/support/topic/permalink-nextpage-doesnt-work?replies=16 – but it’s from six years ago and I can’t find anything there that I can make sense of.

Any help would be greatly appreciated. Thanks.

My site is http://golovegreece.com/ and Permalinks are currently on default.