Hello zerodock. Saffronfs7 may have a point about the SMTP Mail Server (or FTP Server for that matter). In addition to that, make sure that your SMTP server (or FTP server) is properly configured and email account (or FTP server) is not full. With the number of recording emails being received by your account, there is a possibility that the latter is causing this. If the problem still occurs, uninstall and reinstall the WVC80N. The following links may help:
How do I send Motion Detection Videos to my FTP Account using a WVC80N?
Enabling AVI recording on the WVC80N:
Installing WVC80N using the web-based setup page: