API query builder error 500

Hello, I am trying to use the API query builder but I keep on getting Error 500 when fetching.
This simple JS does work, but as I’d like to take advantage of the dynamic tags I tried all sorts of combinations with custom headers etc in the query builder but I always get a 500. Thanks in advance!

This works:

fetch(‘https://tci-living-learning.org/angebotsplattform/seminare.json’, {
method: ‘GET’,
headers: {
‘X-Requested-With’: ‘fetch’,
‘Content-Type’: ‘application/json’
}
})
.then(function(response) {
console.log(‘type:’, response.type);
console.log(‘status:’, response.status);
return response.json();
})
.then(function(data) {
console.log(data);
})
.catch(function(error) {
console.error(‘Fetch error:’, error);
});