squid proxy with openvpn config return HTTP proxy returned Fobidden status code

I have installed squid proxy on server1(OS=centos7 & IP=y.y.y.y & PROXY_PORT=3333) and openvpn server on server2(OS=centos7 & IP=x.x.x.x ).when client wants to connect to openvpn through proxy, gets this error: "on y.y.y.y:3333 HTTP proxy returned Forbiden status code"

squid.conf(server1):

acl localnet src 10.0.0.0/8 # RFC1918 possible internal network
acl localnet src 172.16.0.0/12  # RFC1918 possible internal network
acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
acl localnet src fc00::/7       # RFC 4193 local private network range
acl localnet src fe80::/10      # RFC 4291 link-local (directly plugged) machines
acl SSL_ports port 443
acl Safe_ports port 80      # http
acl Safe_ports port 21      # ftp
acl Safe_ports port 443     # https
acl Safe_ports port 70      # gopher
acl Safe_ports port 210     # wais
acl Safe_ports port 1025-65535  # unregistered ports
acl Safe_ports port 280     # http-mgmt
acl Safe_ports port 488     # gss-http
acl Safe_ports port 591     # filemaker
acl Safe_ports port 777     # multiling http
acl CONNECT method CONNECT
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
http_access allow localhost manager
http_access deny manager
http_access allow localnet
http_access allow localhost
http_access allow all
http_port 3333
coredump_dir /var/spool/squid
refresh_pattern ^ftp:       1440    20% 10080
refresh_pattern ^gopher:    1440    0%  1440
refresh_pattern -i (/cgi-bin/|\?) 0 0%  0
refresh_pattern .       0   20% 4320

openvpn server.conf(server2):

port 1194
proto tcp
dev tun
user nobody
group nobody
persist-key
persist-tun
keepalive 10 120
topology subnet
server 10.8.0.0 255.255.255.0
ifconfig-pool-persist ipp.txt
push "dhcp-option DNS 8.8.8.8"
push "dhcp-option DNS 8.8.4.4"
push "redirect-gateway def1 bypass-dhcp"
dh none
ecdh-curve prime256v1
tls-crypt tls-crypt.key
crl-verify crl.pem
ca ca.crt
cert server_exxNWpWHvKfvioak.crt
key server_exxNWpWHvKfvioak.key
auth SHA256
cipher AES-128-GCM
ncp-ciphers AES-128-GCM
tls-server
tls-version-min 1.2
tls-cipher TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256
client-config-dir /etc/openvpn/ccd
status /var/log/openvpn/status.log
verb 3

openvpn client.ovpn(client):

client
proto tcp-client
remote x.x.x.x 1194
http-proxy y.y.y.y 3333
dev tun
resolv-retry infinite
nobind
persist-key
persist-tun
remote-cert-tls server
verify-x509-name server_exxNWpWHvKfvioak name
auth SHA256
auth-nocache
cipher AES-128-GCM
tls-client
tls-version-min 1.2
tls-cipher TLS-ECDHE-ECDSA-WITH-AES-128-GCM-SHA256
ignore-unknown-option block-outside-dns
setenv opt block-outside-dns # Prevent Windows 10 DNS leak
verb 3
<ca>
 ----something here------
</ca>
<cert>
 ----something here------
</cert>
<key>
 ----something here------
</tls-crypt>

I'm using my proxy in Softether vpn without any error but openvpn gets error.