When placing a bid there are a number of mandatory fields. These are indicated with an orange asterisk. When these fields are completed, it is possible to place a bid.
If this does not work, you may still need to agree to the additional services or content of the Master Agreement. You can agree to the Premium service by clicking on the orange text 'Check out the benefits here and upgrade your profile' (#1 in picture). Then click on 'Upgrade to Premium'. You will automatically return to the bidding screen.
You can agree with the content of the Framework Agreement by clicking on the orange part in the text 'I accept the contents of the HeadFirst V5' (#2 in image). The Framework Agreement will be downloaded. When the document has been downloaded in its entirety, you can check the box in front of this text.