Combin Multiple Calendars

Hi,

I have the same problem as mentioned here:
https://ww.wp.xz.cn/support/topic/multiple-calendars-42/

In the documentation it says that multiple calendars can be combined.
But I cannot get it to work.

Here is my Shortcode:
[gc_list_view g_id_1="[email protected]" g_id_2="[email protected]" orderbysort="ascending" date_format="D. j. M H:i" view_location="yes|map"]

I always get no data returned. If I use the calendar IDs as single shortcodes both of them work and return data.
What am I doing wrong?

Both calendars use the same API key. I also tried adding the key like this:
[gc_list_view g_id_1="[email protected]" g_api_key_1="XXX" g_id_2="[email protected]" g_api_key_2="XXX" orderbysort="ascending" date_format="D. j. M H:i" view_location="yes|map"]
This doesn’t work either.

Thanks a lot for your support!
Matt