Certificate problem with curl, though icecat works

[TK]

Hi all,

Opening this JSON in icecat happens without any error, the connection being 
described as secure:
https://actorws.epa.gov/actorws/chemIdentifier/v01/resolve.json?identifier=MKXZASYAUGDDCJ-NJAFHUGGSA-N

However, doing the same thing with  curl errors out:

$ curl 
https://actorws.epa.gov/actorws/chemIdentifier/v01/resolve.json?identifier=MKXZASYAUGDDCJ-NJAFHUGGSA-N

curl: (60) server certificate verification failed. CAfile: 
/home/user/.guix-profiles/profile/etc/ssl/certs/ca-certificates.crt CRLfile: 
none
More details here: https://curl.haxx.se/docs/sslcerts.html

ca-certificates.crt exists at the CAfile location and CURL_CA_BUNDLE is set 
properly.

Does anyone have an idea what could be going wrong?