Malware URL Phishing

Logging into a familiar travel site I am now getting a warning of malware phishing attempt, saying “Avast web shield has blocked a threat”. Same response on Safari or Firefox. Contacted travel site and their tech has no problem logging into my account with any browser. Malware software run on my computer does not show anything. Is Avast improperly giving message? How can I get around it?
Thanks

You can report a suspected FP (File/Website) here: https://www.avast.com/false-positive-file-form.php

And you can add an exception to Webshield for the given host if you are 100% sure there is no malware there.

to double check the site you can check here as well:

csi.websense.com