Repetier Server API via HTTP Binding

I am trying to use the the http-binding to get informations of my 3d printer, which is connected to repetier server.
When typing in
I get a json message like this
‘{“data”:[{“active”:true,“job”:“none”,“name”:“Anet A8”,“online”:0,“pauseState”:0,“paused”:false,“slug”:“Anet_A8”}]}’

But http binding does not accept the adress:
‘2019-12-15 17:28:22.056 [ERROR] [b.core.service.AbstractActiveService] - Error while executing background thread HTTP Refresh Service
java.util.IllegalFormatConversionException: c != java.util.Date
at java.util.Formatter$FormatSpecifier.failConversion( ~[?:?]
at java.util.Formatter$FormatSpecifier.printCharacter( ~[?:?]
at java.util.Formatter$FormatSpecifier.print( ~[?:?]
at java.util.Formatter.format( ~[?:?]
at java.util.Formatter.format( ~[?:?]
at java.lang.String.format( ~[?:?]
at org.openhab.binding.http.internal.HttpBinding.execute( ~[?:?]
at org.openhab.core.binding.AbstractActiveBinding$BindingActiveService.execute( ~[226:org.openhab.core.compat1x:2.4.0]
at org.openhab.core.service.AbstractActiveService$ [226:org.openhab.core.compat1x:2.4.0]’

What am I doing wrong?

This is an example of the item:
‘String repetierName “bla” {<action>&apikey=0815d12-3299-99be-96e7-7ue23424:10000:JSONPATH($.data[0].slug)]"}’

The api key is anything random, just an example.

Thanks for your help!

Have a look at this thread [Http binding error, Invalid query].

I did not did not read into the stacktrace, so unsure if it matches your case, though I remember having simmilar issues when trying to talk to ESP3D via http binding.
Disabling formatting in the binding configuration did help for me.
Try putting this in /services/http.cfg

# whether to substitute the current time or state value into the URL
# (optional, defaults to true)

Also, before you add JSON transform, it might be good to first retrieve whole data as a string and see if it gets displayed. E.g.:

String repetierName "bla [%s]" { http="<[*))]