This has nothing to do with your issue.
Can you send us the link or example? Is the URL wrapped by marketo or is it a straight URL? Can you access your home page easily from your browser?
First of all, supporting the DNT is mandatory in many western countries (not sure for the US). You should enable it.
What do you mean by timeout ? The link is valid only for a certain duration?
Sure, can I drop you an email instead?