Proton Mail does not support Internationalized Email Addresses

Internationalized Email Addresses, for example প্রোটন@তৌহিদুর.বাংলা is not supported by Proton Mail. When I type my email address in Proton Mail, it weirdly tells me address is not valid.

Note that popular email service providers such as Gmail supports this.

To Reproduce:

Try to send an email to the email address given above.