already tried, not working.
here below in private the admin log credentials for the test site.
please advise, thank you.

hi, thank you for the suggestion.
nothing happened flushing the settings.
anyway, I think I’ve found the issue: the problem seems to be the fact that I tried to set the same custom Portfolio Items Base and Portfolio Categories Base. Might be?
Isn’t it possible to have the same custom base for Portfolio Items and for Portfolio Categories?
ex.
PORTFOLIO ITEM permalink: …/base-name/item-name
PORTFOLIO CATEGORY permalink: …/base-name/category-name
instead of the default
…/items-base-name/item-name
…/categories-base-name/category-name

Simone