Hi @Henk S.
Check if your pages complies with rules specify the criteria for determining a suitable location within an HTML document to inject the...
I've had similar issue in the past. Bad application qualities. To much Js inside.
W3C say <Head> must be at least 1000 Digit. We solved forcing Agent to be placed in <Head>.
Let's me know if solve
Your application --> EDIT --> Advance setup