Whitelist the CGRE parameter in the email header for Google Workspace
Log in to the Google Workspace Admin console and go to "Apps > Google Workspace > Gmail"
Scroll down the screen and click on "Compliance".
Scroll down to the section "Content Compliance" and click on "Add another rule"
Configure the fields in the window that appears with the following parameters:
Enable the checkbox "Inbound"
Enable the checkbox "Entire - receiving"
Under the tab "Add expressions that describe the content to search for in each message", click and select "If ANY of the following match the message"
Under the wording "If ANY of the following match the message", click on "Add"
Configure the fields in the window that appears with the following parameters:
Select "Advanced content match"
Set "Location" to "Full headers"
Set "Match type" to "Contains text"
Enter the following value as "Content":
CGRE: en2358nfwf348fnw932jdo4fe4rrewffd
Click on "Save"
Scroll down the window, select the checkbox "Bypass spam filter for this message" and click on "Save"