Thanks abm, I can't quite replicate your example below because I don't have dynamic content from Dynamics at this stage; I am starting from a SharePoint list entry and trying to lookup a GUID in Dynamics. Using your example below, I tried to filter the query as shown in this screenshot, but it is giving me a syntax error "Syntax error at position 40 in '_emailaddress1_value eq fred@synaxiscorp.com'.\", where fred@synaxiscorp.com was the value pulled from the SharePoint dynamic content (i.e., Created By Email, as shown in screenshot). Any idea where I'm going wrong with my syntax?

Forgot to mention: emailaddress1 is the field name in the Dynamics Contacts entity that I'm trying to use for the lookup.