Is money earned from working as a mailman in Denmark permissible or forbidden, especially when delivering materials containing objectionable content or dealing with entities that engage in forbidden activities, and what should be done with money earned previously and what will be earned later until the end of the contract?

It is not permissible to work in buying or selling immoral magazines due to their containing forbidden content. It is obligatory to repent from this work, and it is not permissible to continue in it after knowing of its prohibition. What was obtained before knowing of the prohibition is forgiven, and the void contract must be disposed of by any possible means, even if it results in financial loss.