We don't currently have Vivo enable on our Frog...! but I got this message yesterday....
Following our email of 23rd September, we have an update for customers who were experiencing problems with single sign-on (SSO) from Frog.
Frog have now upgraded their Vivo widget, and this seems to have resolved the underlying problem. Affected Vivo customers can now upgrade to the latest version of Frog's Vivo widget (v1.2) and this should fix the SSO issue without requiring any changes to the security settings of Internet Explorer.
If you changed your security settings in IE as a result of our previous email, we suggest that you revert the workaround by changing the IE setting
Internet Options>Security>Internet>
Custom level>Miscellaneous>Access data source across domains to Disabled