Strongswan IKEv2 for iOS devices

I want to connect a Strongswan IKEv2 VPN on iOS devices. It uses FreeRADIUS server for AAA of users.

It's already working perfectly on Android and Windows devices. but when I try to connect using the iOS device it shows the below logs. I'm manually making a VPN profile and manually Installing the .p12 certificates for server authetication

server hostname: nas.example.com
server ip: 89.89.89.89
client ip: 99.99.99.99

ipsec.conf

config setup
    charondebug="all"
    uniqueids=no

conn ikev2-vpn
    auto=add
    compress=yes
    type=tunnel
    keyexchange=ikev2
    fragmentation=yes
    forceencaps=yes
    ike=aes256-sha1-modp1024,3des-sha1-modp1024!
    esp=aes256-sha1,3des-sha1!
    dpdaction=clear
    dpddelay=3600s
    dpdtimeout=5s
    rekey=no
    left=%any
    leftid=89.89.89.89
    leftcert=vpn-server-cert.pem
    leftsendcert=always
    leftsubnet=0.0.0.0/0
    right=%any
    rightid=%any
    rightauth=eap-radius
    #rightauth=eap-mschapv2
    rightdns=8.8.8.8,8.8.4.4
    rightsourceip=10.10.10.0/24
    rightsendcert=never
    eap_identity=%identity

server side logs

Oct 06 02:14:43 nas.example.com charon[3607]: 13[NET] sending packet: from 89.89.89.89[4500] to 99.99.99.99[4500] (792 bytes)
Oct 06 02:15:00 nas.example.com charon[3607]: 14[NET] received packet: from 99.99.99.99[500] to 89.89.89.89[500] (604 bytes)
Oct 06 02:15:00 nas.example.com charon[3607]: 14[ENC] parsed IKE_SA_INIT request 0 [ SA KE No N(REDIR_SUP) N(NATD_S_IP) N(NATD_D_IP) N(FRAG_SUP) ]
Oct 06 02:15:00 nas.example.com charon[3607]: 14[IKE] 99.99.99.99 is initiating an IKE_SA
Oct 06 02:15:00 nas.example.com charon[3607]: 14[IKE] 99.99.99.99 is initiating an IKE_SA
Oct 06 02:15:00 nas.example.com charon[3607]: 14[IKE] remote host is behind NAT
Oct 06 02:15:00 nas.example.com charon[3607]: 14[IKE] DH group MODP_2048 inacceptable, requesting MODP_1024
Oct 06 02:15:00 nas.example.com charon[3607]: 14[ENC] generating IKE_SA_INIT response 0 [ N(INVAL_KE) ]
Oct 06 02:15:00 nas.example.com charon[3607]: 14[NET] sending packet: from 89.89.89.89[500] to 99.99.99.99[500] (38 bytes)
Oct 06 02:15:01 nas.example.com charon[3607]: 15[NET] received packet: from 99.99.99.99[500] to 89.89.89.89[500] (476 bytes)
Oct 06 02:15:01 nas.example.com charon[3607]: 15[ENC] parsed IKE_SA_INIT request 0 [ SA KE No N(REDIR_SUP) N(NATD_S_IP) N(NATD_D_IP) N(FRAG_SUP) ]
Oct 06 02:15:01 nas.example.com charon[3607]: 15[IKE] 99.99.99.99 is initiating an IKE_SA
Oct 06 02:15:01 nas.example.com charon[3607]: 15[IKE] 99.99.99.99 is initiating an IKE_SA
Oct 06 02:15:01 nas.example.com charon[3607]: 15[IKE] remote host is behind NAT
Oct 06 02:15:01 nas.example.com charon[3607]: 15[ENC] generating IKE_SA_INIT response 0 [ SA KE No N(NATD_S_IP) N(NATD_D_IP) N(FRAG_SUP) N(MULT_AUTH) ]
Oct 06 02:15:01 nas.example.com charon[3607]: 15[NET] sending packet: from 89.89.89.89[500] to 99.99.99.99[500] (316 bytes)
Oct 06 02:15:01 nas.example.com charon[3607]: 03[NET] received packet: from 99.99.99.99[4500] to 89.89.89.89[4500] (484 bytes)
Oct 06 02:15:01 nas.example.com charon[3607]: 03[ENC] unknown attribute type (25)
Oct 06 02:15:01 nas.example.com charon[3607]: 03[ENC] parsed IKE_AUTH request 1 [ IDi N(INIT_CONTACT) N(MOBIKE_SUP) IDr CPRQ(ADDR DHCP DNS MASK ADDR6 DHCP6 DNS6 (25)) N(ESP_TFC_PAD_N) N(NON_FIRST_FRAG) SA TSi TSr ]
Oct 06 02:15:01 nas.example.com charon[3607]: 03[CFG] looking for peer configs matching 89.89.89.89[89.89.89.89]...99.99.99.99[varun]
Oct 06 02:15:01 nas.example.com charon[3607]: 03[CFG] selected peer config 'ikev2-vpn'
Oct 06 02:15:01 nas.example.com charon[3607]: 03[IKE] initiating EAP_IDENTITY method (id 0x00)
Oct 06 02:15:01 nas.example.com charon[3607]: 03[IKE] received ESP_TFC_PADDING_NOT_SUPPORTED, not using ESPv3 TFC padding
Oct 06 02:15:01 nas.example.com charon[3607]: 03[IKE] peer supports MOBIKE
Oct 06 02:15:01 nas.example.com charon[3607]: 03[IKE] authentication of '89.89.89.89' (myself) with RSA signature successful
Oct 06 02:15:01 nas.example.com charon[3607]: 03[IKE] sending end entity cert "C=US, O=nas.example.com, CN=89.89.89.89"
Oct 06 02:15:01 nas.example.com charon[3607]: 03[ENC] generating IKE_AUTH response 1 [ IDr CERT AUTH EAP/REQ/ID ]
Oct 06 02:15:01 nas.example.com charon[3607]: 03[ENC] splitting IKE message with length of 1980 bytes into 2 fragments
Oct 06 02:15:01 nas.example.com charon[3607]: 03[ENC] generating IKE_AUTH response 1 [ EF(1/2) ]
Oct 06 02:15:01 nas.example.com charon[3607]: 03[ENC] generating IKE_AUTH response 1 [ EF(2/2) ]
Oct 06 02:15:01 nas.example.com charon[3607]: 03[NET] sending packet: from 89.89.89.89[4500] to 99.99.99.99[4500] (1248 bytes)
Oct 06 02:15:01 nas.example.com charon[3607]: 03[NET] sending packet: from 89.89.89.89[4500] to 99.99.99.99[4500] (792 bytes)
Oct 06 02:15:12 nas.example.com charon[3607]: 16[JOB] deleting half open IKE_SA with 99.99.99.99 after timeout

Any help will be appreciated.
Thanks