Thank you for bringing your question to the community! I do see the campaign you linked, and was able to view it correctly on my mobile device. I know though that many mobile devices do display coding and web-pages differently, and this is a challenge on both emails, as well as their web-page archives. I noticed that the campaign you linked to was one created with our legacy editor. The newer 3rd Generation Editor has better built in mobile responsiveness than it's older legacy counterpart, and this responsiveness should carry over to the archive as well. I would suggest moving into that newer editor. It looks like you were likely using the 'Basic Newsletter' template, which we have available in the new editor as well, so you can even keep the same look!
In your account just click 'Create' in the upper right side fo the main page, or the campaigns page, and choose the template of your choice.
Aaron_H Community & Social Media Support
If you find my post helpful, and it answers your question, please mark it as an "Accepted Solution" by clicking the Accept as Solution button in the bottom right hand corner of this post.
Increase your profitability by integrating your email marketing and social media. Download this guide and learn how you can achieve great results with email marketing and social media combined!