Of course I missed to attach the log file. Here it is.
Mar 10 09:02:16 ppcl001 NetworkManager[5985]: <info> Starting VPN service 'strongswan'... Mar 10 09:02:16 ppcl001 NetworkManager[5985]: <info> VPN service 'strongswan' started (org.freedesktop.NetworkManager.strongswan), PID 8843 Mar 10 09:02:16 ppcl001 charon: 00[DMN] Starting IKEv2 charon daemon (strongSwan 4.5.2) Mar 10 09:02:16 ppcl001 charon: 00[KNL] listening on interfaces: Mar 10 09:02:16 ppcl001 charon: 00[KNL] eth0 Mar 10 09:02:16 ppcl001 charon: 00[KNL] 10.10.10.192 Mar 10 09:02:16 ppcl001 charon: 00[KNL] fe80::2ad2:44ff:fe3d:8674 Mar 10 09:02:16 ppcl001 charon: 00[LIB] plugin 'stroke' failed to load: /usr/lib/ipsec/plugins/libstrongswan-stroke.so: cannot open shared object file: No such file or directory Mar 10 09:02:16 ppcl001 charon: 00[CFG] sql plugin: database URI not set Mar 10 09:02:16 ppcl001 charon: 00[LIB] plugin 'sql': failed to load - sql_plugin_create returned NULL Mar 10 09:02:16 ppcl001 charon: 00[LIB] plugin 'updown' failed to load: /usr/lib/ipsec/plugins/libstrongswan-updown.so: cannot open shared object file: No such file or directory Mar 10 09:02:16 ppcl001 charon: 00[CFG] loaded 0 RADIUS server configurations Mar 10 09:02:16 ppcl001 charon: 00[LIB] plugin 'medsrv' failed to load: /usr/lib/ipsec/plugins/libstrongswan-medsrv.so: cannot open shared object file: No such file or directory Mar 10 09:02:16 ppcl001 charon: 00[CFG] mediation client database URI not defined, skipped Mar 10 09:02:16 ppcl001 charon: 00[LIB] plugin 'medcli': failed to load - medcli_plugin_create returned NULL Mar 10 09:02:16 ppcl001 NetworkManager[5985]: <info> VPN service 'strongswan' appeared; activating connections Mar 10 09:02:16 ppcl001 charon: 00[CFG] HA config misses local/remote address Mar 10 09:02:16 ppcl001 charon: 00[LIB] plugin 'ha': failed to load - ha_plugin_create returned NULL Mar 10 09:02:16 ppcl001 charon: 00[DMN] loaded plugins: test-vectors curl ldap aes des sha1 sha2 md5 random x509 revocation constraints pubkey pkcs1 pgp pem openssl fips-prf gmp agent pkcs11 xcbc hmac ctr ccm gcm attr kernel-netlink resolve socket-raw farp eap-identity eap-aka eap-md5 eap-gtc eap-mschapv2 eap-radius eap-tls eap-ttls eap-tnc nm dhcp led addrblock Mar 10 09:02:16 ppcl001 charon: 00[JOB] spawning 16 worker threads Mar 10 09:02:16 ppcl001 charon: 04[LIB] L1 - version: ASN1 tag 0x02 expected, but is 0x30 Mar 10 09:02:16 ppcl001 charon: 04[LIB] building CRED_PRIVATE_KEY - RSA failed, tried 8 builders Mar 10 09:02:16 ppcl001 charon: 04[LIB] L1 - version: ASN1 tag 0x02 expected, but is 0x30 Mar 10 09:02:16 ppcl001 charon: 04[LIB] building CRED_PRIVATE_KEY - RSA failed, tried 8 builders Mar 10 09:02:28 ppcl001 charon: 04[LIB] L1 - version: ASN1 tag 0x02 expected, but is 0x30 Mar 10 09:02:28 ppcl001 charon: 04[LIB] building CRED_PRIVATE_KEY - RSA failed, tried 8 builders Mar 10 09:02:28 ppcl001 NetworkManager[5985]: get_secrets: assertion `secrets_idx < SECRETS_REQ_LAST' failed