Mailbox blocked for oversizing

Mailbox blocked for oversizing

Hi,

I have the warning that my mailbox account is out of space. After archiving some e-mails the mail volume raised several times as seen in mail accounts settings.

What am I doing wrong and what can I do to be unblocked?

P.S. This looks unreal when my email accounts take about 50000 Mb of space while only 5000 Mb allowed...