Error while converting a raw picture from Sony Alpha A1

Good morning (german time zone),

I try to convert the raw pictures taken by a sSny A1 to jpg, but I get
an error message:

gm convert /home/markus/temp/SA100255.ARW /home/markus/temp/SA100255.jpg
Cannot decode file /home/markus/temp/SA100255.ARW
gm convert: "dcraw" -c -w -6 -T "/home/markus/temp/SA100255.ARW" >
"/tmp/gmdkMKhP".
gm convert: Delegate failed ("dcraw" -c -w -6 -T "%i" > "%o").

When I do the same with pictures taken on my Sony Alpha A7SIII it
works, so I guess there is a bug in gm.
Since I am very new here, I have no idea how to upload the picture so
the developers can analyse the problem. The picture is about 66MB.

Thanks for Your assistance in advance
Markus