No power with jump box?

My 2013 Cls 550 want start after jumping with a jump box there isn't any dash lights its like i have on power at all know and the sos button by the rearview mirror is blinking

This could be the battery is so dead it will not allow the jumpbox to work. Remove the jump box and use a voltameter to see how many volts the battery has naturally. It should have at least 10.5 volts or the jumper wont work. This guide can help

https://www.2carpros.com/articles/how-to-use-a-voltmeter

If that checks out there is a main relay that I would check use a CAN scanner because I have also seen the SAM module go out which can cause this issue as well you can get a CAN scanner from Amazon for about $30.00 here is a video to show you how.

https://youtu.be/u-4syLc-ifQ

here is a scanner link

https://amzn.to/3o41KcZ

I have included how to change the SAM module out in the diagrams below. Check out the diagrams (Below). Let us know what happens and please upload pictures or videos of the problem.