Google Translation:

UPC Webmail

Dear Users!

We would like to draw your attention to the fact that the technical support for UPC Webmail and the related e-mail service will be discontinued by the service provider on March 1, 2021.
If you have an address ending in @ upcmail.hu, @ chello.hu, @ monornet.hu, @ upctelekom.hu, @ upc.hu or @ vodamail.hu, please replace it, as the non-working e-mail address may result in the risk of permanent loss of your user account at a later date.

You can check the currently entered e-mail addresses in the Settings menu and change them if necessary.