Archive posts not showing

Hello.

I think this is a theme problem and would appreciate any help you can give.

Ok, this is what is happening.

When “browsing monthly archive”, Instead of making a link to:

https://www.student-bites.co.uk/index.php/2006/09/page/2

wordpress makes a link to:
https://www.student-bites.co.uk/index.php/page/2

The first URL I posted above will show you the next posts in september.

Any suggestions.