Import with a specified nickname doesn't work as expected
The import function works well if no nickname is specified; it also works well if the specified nickname is not taken already (or existed ever, see #1383 ).
However, if a nickname is specified and the nickname is the same as a removed channel, there is no warning, and the import tried to happen. However, after redirect, an incorrectly rendered page appears and the only way to leave that page is "logout". After logout and re-login, no channel is created. (I suppose it's the same for a channel currently existing.)
This ccould either be solved by assigning a random nickname (as the hint below the "nickname" field says), or disabling the "import" button until no conflict.