Using External Forms CallBackURL

[font=Calibri, sans-serif]My team and I are having issues leaving to an external form and then coming back. We have tried several different combinations for the callback URL and have been unsuccessful. We’ve also consulted the online help documentation.[/font]
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[font=Calibri, sans-serif]Here’s what we’re currently getting when we navigate back to the system.[/font]
[font=Calibri, sans-serif][img]att1[/img][/font]