Can't login to Market Place in Minecraft Win10

Hello everyone!

Recently I got Minecraft for Win10 gifted & I use the XBox Companion App to launch the game.

I am logged in to Windows, I am logged in to the XBox App, but I can't login to Minecraft itself & therefore I can't login to the Market Place.

It only says ''Error number -5''

I wrote a ticket to the email address which is shown in that error box (help.mojang.com) but they said basically that it's none of their business & told me to ask microsoft for help.

& I did that as well. Twice. & this was about 2 weeks ago, without any reply from their support.

I somehow was able to buy myself 2 maps from the Market Place using my web browser. Those maps were added to my game & I was able to play them.

But today I was browsing for some more maps & added some free maps to my game.

The thing is: those games were added to my Minecraft but I can't play them. Even though they were for free, I have to unlock them. & I can only unlock them by logging in to the market place, which still isn't working. & I have no access to the maps I already
paid for anymore, because those locked, free maps are on the top of the selection list when I want to create a new map from my collection. & I can't scroll through my collection because I have to login to the market place to do so as well. Means I have no
access to stuff I paid for. & I can't find a button which lets me delete those free, locked maps from my collection.

My microsoft account is verified. I was able to login to other games from microsoft before with that account as well. It's really just minecraft & that market place which won't work.

I would really appreciate some help!

:)