Cannot Activate Bitdefender Antivirus

Hi. Today I installed Bitdefender Antivirus Free Edition on my computer. After the installation, I was asked to log in to My Bitdefender in order to continue using the product after 29 days. However, after I pressed the "Login" button, an error dialog appeared, saying that the connection to the server has failed, and the product couldn't be activated.

Since I encounter no problems connecting to the Internet (I'm using wired Ethernet connection), I don't think my computer has a connection problem. Also, Bitdefender is the only antivirus product I installed on my computer, so it's unlikely to be a problem regarding conflicts between antivirus products.

Any solutions?