Hello dear community,
I am currently running into trouble with a custom email template I created for a client. Most of the markup was done within the MJML framework with slight, cautious modifications by myself later.
Within the Litmus previews and remote renderings everything looks fine in Outlook 2016 and 2019 on Windows 10, see screenshots attached (except for the non-rounded buttons which are acceptable). However as you can see in the other attached screenshot, the client is having significant display issues with margins between tables and and broken widths of modules on his machiens.

Here is a link to the template’s HTML:
http://letrip.de/staging/rr-newsletter-2020/rr-newsletter-template-2020-cleverreach.html

Maybe somebody here has an idea what might cause the issue?

Screenshot of the Litmus rendering Screenshot of the buggy rendering