New product not showed or canonicals changed

-- HikaShop version -- : 2.6.1
-- Joomla version -- : 3.4.8
-- PHP version -- : 5.6.17
-- Browser(s) name and version -- : Different

When I create a new product, it’s showed on the product page but if you click on it, it gives a 404-error. It doesn’t matter if I specify the canocical in the product page or not.
In configurations features SEF “delete product and category id” is set to yes and Force SEF is "Use canonical URL if specified".

You suggested in an earlier reply to change the above settings to no and no (“You can keep the canonical URLs. Just turn off the "force canonical URLs on listings" setting of the HikaShop configuration and the system won't use the canonical URLs on the listings but it will still be used as canonical URL”). But, if I change both (above specified) setting to ‘no’ and ‘no’, then it shows the new product and the old ones, but with new URL’s (the product-ID is in it). So all my old URL’s will be showed in a different way and it will change of course the way Google will index it. And all the URL’s which are indexed by Google are wrong and will result in an error. When a product has different categories, you cannot choose your own preferred URL. Setting one of the two (above mentioned) settings to no, than I have the same kind of problems.

Do you have a solution for this so that I can create new products and keep my old (canonical) URL’s?

Thank you for your reply.
My alias was exactly the same as the product name. The product name was: Test3, the alias test3 and the canonical /category1/test3.
I tried different things and suddenly I saw that a product name with at least one space, e.g. Test 3 (alias test-3) solved the problem. I tried different product names and in any case a product name without a space gave the problem (404 error). So it seems that a product name needs a space in it and/or an alias at least one -.