Hope it's OK to use this topic, I think this is a related problem. I have the same error ("Resume impossible! Either resume via previously used multihost or reset and start from scratch!") with mega.nz except I've never used a multihost. I didn't even know what a multihost was before I found this topic.
My host settings:
https://i.imgur.com/6R9jW3Q.png
(it's just 1 account for mega.co.nz)
Here's my log. Sorry if it's a lot to sift through, I wasn't sure which parts would be relevant.
30.08.20 06.28.02 <--> 29.08.20 16.11.52 jdlog://9192225302851/