The microsoft website clearly indicates the store closes on December 16, 2019, the website information is wrong, microsoft closed the store for hardreset devices.
I have three Lumias: one of them was resetted in Nov 14 and only today morning I was able to singn in to MS account (it was another error, figure it). After this sign in, I've got this famous c101a006. No update or instalation possible.
The other two phones were resetted two years ago and functional until Nov 14, but since then they can't load "my apps" section in the Store: c101a006 error, too. Luckily, these phones have their apps installed, but no new instalations are possible.
So, this error is for everybody :D . But yes, the resetted devices are in limbo.
PS: if you web search this c101a006 error, you'll find it since 2012. Seven years + . Fabulous, MS!