ovpn-out1: terminating... - unknown cipher alg or key size

I have followed all guides to troubleshoot but I can’t get my OpenVPN to work

In my linux VPS VPN server, this is my server-tcp.conf:

port 1194
proto tcp
dev tun
ca ca.crt
cert server.crt
key server.key
dh dh2048.pem
plugin /usr/lib/openvpn/openvpn-plugin-auth-pam.so login
verify-client-cert none
username-as-common-name
server 10.6.0.0 255.255.255.0
ifconfig-pool-persist ipp.txt
push "redirect-gateway def1 bypass-dhcp"
push "dhcp-option DNS 8.8.8.8"
push "dhcp-option DNS 8.8.4.4"
keepalive 5 30
comp-lzo
persist-key
persist-tun
status openvpn-tcp.log
verb 3

I always get

ovpn-out1: terminating... - unknown cipher alg or key size

no matter what cipher I tried to use.

In my server, I don’t know how to change cipher in there. I can’t find in my conf file.
Any help is very much appreciated <3