zmdownload-accl.zoho.com infected with URL:Blacklist

zmdownload-accl.zoho.com infected with URL:Blacklist

When I try to download an email attachment my antivirus software (Avast Business Antivirus Pro) is blocking the connection and displays the following message:

We've safely aborted connection on zmdownload-accl.zoho.com because it was infected with URL:Blacklist

Full message attached.

I'd appreciate some advice as this is preventing me from working at the moment.

Regards
Stu