klm's website is awful!

ams-iad
Bought ticket on Delta but flying on KLM metal.

just created my klm Flying Blue acct.
i cant add my delta confirmation # to my klm acct.
"Sorry, we couldn't add your booking. Please check if you entered the correct booking code and try again, or contact us."

yet when i'm logged out, i can see my flight AND MY NAME by entering Delta's conf #.
w t f?!