login on cart acting weird

[fabvincent]

Hi, I'm confronted to a thing I really could not expect :
I'm using VM 2.0.26 my shopping cart is up and running... Or so I thought... I have a simple shopper test login which is working (I can place orders that follow through), if I create a new login as a new shopper, the account is getting created but when this new shopper gets to the cart and is asked to login to continue, he is redirected to the ....index.php/component/users/?view=login instead of remaining on the cart...
What's happening here?
Is there any special feature to my test account that I should apply to the newcomers?
Thanks in advance, this is driving me insane.

[fabvincent]

Just in case that can give a hint to someone :
If I change the password manually in my virtuemart admin, the cart page is acting correctly and forwarding the customer to the cart with the personal informations. So I guess the form is not sending the proper infos or???
In advance, thanks.