Are you using VM webmail? Or an email client? Which one/what device? There can be many reasons, but the client won't always tell you, please try to get the specific error code (VMxxx), and we can help with diagnosis.
If you have important email to send, you can log on to webmail and that will work, as webmail goes more securely and through different servers. But don't delay in doing the search - who knows what other malware has been installed on your home network, plus your system is spamming the world! When you have cleared your system, the spamhaus listing will automatically (maybe 24 hours?) change and VM will let your client work again.
Common culprits are HOLA free VPN, Amazon firesticks with rogue software, smart TV, anything that connects to the internet is a suspect. Best wishes, let us know if you require assistance. We want you safe again.