Strongswan Swanctl not happy with certificate - ? invalid value for: certs

Hi guys.

I'm migrating my swanctl roadwarrior configs from CentOS - where it all worked - but oWRT's swanctl is not happy:

-> $ swanctl --load-all
loading '/etc/swanctl/x509/my-server.crt' failed: parsing X509 certificate failed
...

I thought 'strongswan-mod-pem' should fix that but installing did not help.
I have:

-> $ opkg list-installed *swan* 
strongswan - 5.9.2-1
strongswan-charon - 5.9.2-1
strongswan-ipsec - 5.9.2-1
strongswan-minimal - 5.9.2-1
strongswan-mod-aes - 5.9.2-1
strongswan-mod-gmp - 5.9.2-1
strongswan-mod-hmac - 5.9.2-1
strongswan-mod-kernel-libipsec - 5.9.2-1
strongswan-mod-kernel-netlink - 5.9.2-1
strongswan-mod-nonce - 5.9.2-1
strongswan-mod-pem - 5.9.2-1
strongswan-mod-pubkey - 5.9.2-1
strongswan-mod-random - 5.9.2-1
strongswan-mod-sha1 - 5.9.2-1
strongswan-mod-socket-default - 5.9.2-1
strongswan-mod-stroke - 5.9.2-1
strongswan-mod-updown - 5.9.2-1
strongswan-mod-vici - 5.9.2-1
strongswan-mod-x509 - 5.9.2-1
strongswan-mod-xcbc - 5.9.2-1
strongswan-swanctl - 5.9.2-1

I need only minimal install for roadwarrior IKEv2 with RSA and EAP.
What am I missing?

many thanks, L.