Reforis - Forbidden

Hi,

I just did an upgrade right after a factory reset on one of my Turris Mox. It upgraded to TurrisOS 5.1.5 e29002471734dbba927d43f0b23818ddc5f551a7. I cannot access Reforis. After login, I have the following message from the webserver:

Forbidden

You don’t have the permission to access the requested resource. It is either read-protected or not readable by the server.

I performed a flash from the Internet, which solved this issue.

Can you explain this solution?