If you get the error message 'Invalid BIC' when trying to make a EUR withdrawal this probably means that your bank is not part of the network of SEPA-reachable banks. The list of participating banks is updated on a weekly basis. Our bank uses the list maintained and provided by the German Bundesbank in Frankfurt, Germany.
For more information on the availability of EUR withdrawals check this article.
If your bank is part of the SEPA network but you still get the error, this could mean that withdrawals to your bank are restricted because past withdrawals have frequently been rejected or returned. In that case please contact Support.