Hi @Viktorio! I'm assuming you're on the Free Plan? In that case, only your 3 last created boards are active – the rest becomes read-only. The easiest way to regain access (without upgrading) is to duplicate the read-only board. The duplicate version will then become active. However, another board will then become read-only instead.

@Viktorio - To protect you and your colleague’s personal information, I have redacted your email addresses.

You can read more about the 3-editable-boards (and other) limitations of the Free Plan in the Free Plan  Help Center article.

Thank you very much guys. It works again. Thank you