Problem with generating isochrones from layer in QGis ORS-tools

I have a new laptop and installed QGis 3.30.0 and the ORS-tools plugin. I want to generate Isochrones from a layer. I have a token and generating an isochrone from a single point works fine. However once I try to do this from a layer with single points I get the following error, any ideas how tot solve this?:

Traceback (most recent call last):
File “C:\Users/gesl/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\ORStools\proc\”, line 155, in processAlgorithm
response = ors_client.request(‘/v2/isochrones/’ + profile, {}, post_json=params)
File “C:\Users/gesl/AppData/Roaming/QGIS/QGIS3\profiles\default/python/plugins\ORStools\common\”, line 152, in request
f"url: {self.url}\nParameters: {json.dumps(body, indent=2)}",
File “C:\PROGRA1\QGIS331.0\apps\Python39\lib\json_init
.py”, line 234, in dumps
return cls(
File “C:\PROGRA1\QGIS331.0\apps\Python39\lib\json\”, line 201, in encode
chunks = list(chunks)
File “C:\PROGRA1\QGIS331.0\apps\Python39\lib\json\”, line 431, in _iterencode
yield from _iterencode_dict(o, _current_indent_level)
File “C:\PROGRA1\QGIS331.0\apps\Python39\lib\json\”, line 405, in _iterencode_dict
yield from chunks
File “C:\PROGRA1\QGIS331.0\apps\Python39\lib\json\”, line 438, in _iterencode
o = _default(o)
File “C:\PROGRA1\QGIS331.0\apps\Python39\lib\json\”, line 179, in default
raise TypeError(f’Object of type {} ’
TypeError: Object of type QVariant is not JSON serializable

Execution failed after 0.03 seconden_