WordPress /page/2 404 pagination problem – what to do?

I came across the /page/2 404 pagination problem and tried to find a solution. I’ve read some suggestions, but it didn’t help yet.

Working:
http://pandasnacozinha.com.br/bolos-doces-e-sobremesas/

Not working:
http://pandasnacozinha.com.br/bolos-doces-e-sobremesas/page/2/

I’ve been trying to figure this out for hours. I understand WordPress assumes “page” is a post from the category “bolos, doces e sobremesas” since my permalink structure is /%category%/%postname%/ but I don’t know how to fix it.

I had the same problem and I noticed that in the 'posts_per_page = 6' and 'Settings/Reading on ‘options-reading’ WordPress argument, I was set to 10. When I put everything to the same value (6 in my case) everything started working again.