Unable to block email on UTRS

[5albertsquare]

When trying to block an email address on UTRS I get A database error occured when attempting to process your request:
array ( 0 => '23000', 1 => 1048, 2 => 'Column 'target' cannot be null', )

Nothing is blank or set to null though.

[dqwiki]

I am not able to reproduce this. What appeal is it on?