iTunes Store Error message 5002

Since today - never had a problem with it - I have a problem in downloading apps & music from different machines using same apple-id. After having selected the download or purchase button (whilst being signed in) the download is instandly cancelled and an error message occurs refering to a code 5002.

It seems not to related to my hardware being used as from any client the same message occurs

It seems therefor to relate to my itunes account, but how should I resolve this