Allowing access to my server's ports when the server is connected to OpenVPN (Ubuntu Server 18.10)

I've recently installed Ubuntu Server 18.10, and would like to open some ports (i.e. SSH, HTTP) to be accessible to the public. However, because of my ISP's constraints (my ISP is on a CGNAT and will not allow me to open ports), I'm connecting the Ubuntu server to a VPN that allows me to forward ports to my local machine via OpenVPN.

I am already able to connect properly to the OpenVPN server, and my VPN already allows port forwarding and has already forwarded the ports from the VPN. I can also ping the Ubuntu Server using my VPN's public IP address. However, I couldn't connect to my Ubuntu Server's ports (22/80) despite forwarding the ports on my VPN server.

Is there something I need to do on my Ubuntu Server to make it work? I'm trying to understand both iptables and ufw, and tried several topics around the Internet, but I couldn't seem to make it work. I'm not a network guy so I hope you could guide me how to set up ufw and/or iptables to allow my Ubuntu Server's ports to be accessible to my VPN's public IP.

Hope someone could help me out. Thanks!

Here's the output of my ufw status, iptables, and ifconfig for reference:

ufw status

$ sudo ufw status verbose
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing), deny (routed)
New profiles: skip
To Action From
-- ------ ----
22 ALLOW IN Anywhere
80 ALLOW IN Anywhere
22 (v6) ALLOW IN Anywhere (v6)
80 (v6) ALLOW IN Anywhere (v6)

iptables

$ sudo iptables -L
Chain INPUT (policy DROP)
target prot opt source destination
KUBE-FIREWALL all -- anywhere anywhere
KUBE-NODEPORT-NON-LOCAL all -- anywhere anywhere /* Ensure that non-local NodePort traffic can flow */
ufw-before-logging-input all -- anywhere anywhere
ufw-before-input all -- anywhere anywhere
ufw-after-input all -- anywhere anywhere
ufw-after-logging-input all -- anywhere anywhere
ufw-reject-input all -- anywhere anywhere
ufw-track-input all -- anywhere anywhere
Chain FORWARD (policy DROP)
target prot opt source destination
DOCKER-USER all -- anywhere anywhere
DOCKER-ISOLATION-STAGE-1 all -- anywhere anywhere
ACCEPT all -- anywhere anywhere ctstate RELATED,ESTABLISHED
DOCKER all -- anywhere anywhere
ACCEPT all -- anywhere anywhere
ACCEPT all -- anywhere anywhere
ufw-before-logging-forward all -- anywhere anywhere
ufw-before-forward all -- anywhere anywhere
ufw-after-forward all -- anywhere anywhere
ufw-after-logging-forward all -- anywhere anywhere
ufw-reject-forward all -- anywhere anywhere
ufw-track-forward all -- anywhere anywhere
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
KUBE-FIREWALL all -- anywhere anywhere
ufw-before-logging-output all -- anywhere anywhere
ufw-before-output all -- anywhere anywhere
ufw-after-output all -- anywhere anywhere
ufw-after-logging-output all -- anywhere anywhere
ufw-reject-output all -- anywhere anywhere
ufw-track-output all -- anywhere anywhere
Chain DOCKER (1 references)
target prot opt source destination
Chain DOCKER-ISOLATION-STAGE-1 (1 references)
target prot opt source destination
DOCKER-ISOLATION-STAGE-2 all -- anywhere anywhere
RETURN all -- anywhere anywhere
Chain DOCKER-ISOLATION-STAGE-2 (1 references)
target prot opt source destination
DROP all -- anywhere anywhere
RETURN all -- anywhere anywhere
Chain DOCKER-USER (1 references)
target prot opt source destination
RETURN all -- anywhere anywhere
Chain KUBE-FIREWALL (2 references)
target prot opt source destination
DROP all -- anywhere anywhere /* kubernetes firewall for dropping marked packets */ mark match 0x8000/0x8000
Chain KUBE-NODEPORT-NON-LOCAL (1 references)
target prot opt source destination
Chain ufw-after-forward (1 references)
target prot opt source destination
Chain ufw-after-input (1 references)
target prot opt source destination
ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:netbios-ns
ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:netbios-dgm
ufw-skip-to-policy-input tcp -- anywhere anywhere tcp dpt:netbios-ssn
ufw-skip-to-policy-input tcp -- anywhere anywhere tcp dpt:microsoft-ds
ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:bootps
ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:bootpc
ufw-skip-to-policy-input all -- anywhere anywhere ADDRTYPE match dst-type BROADCAST
Chain ufw-after-logging-forward (1 references)
target prot opt source destination
LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] "
Chain ufw-after-logging-input (1 references)
target prot opt source destination
LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] "
Chain ufw-after-logging-output (1 references)
target prot opt source destination
Chain ufw-after-output (1 references)
target prot opt source destination
Chain ufw-before-forward (1 references)
target prot opt source destination

ifconfig

$ sudo ifconfig
docker0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 inet 172.17.0.1 netmask 255.255.0.0 broadcast 172.17.255.255 ether 02:42:a9:b0:c9:f2 txqueuelen 0 (Ethernet) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.1.254 netmask 255.255.255.0 broadcast 192.168.1.255 inet6 fe80::20c:29ff:fee1:76a8 prefixlen 64 scopeid 0x20<link> ether 00:0c:29:e1:76:a8 txqueuelen 1000 (Ethernet) RX packets 86235 bytes 129085349 (129.0 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 21648 bytes 3799697 (3.7 MB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 20111 bytes 4496081 (4.4 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 20111 bytes 4496081 (4.4 MB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
tun0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST> mtu 1500 inet xx.xx.xx.xx netmask xx.xx.xx.xx destination xx.xx.xx.xx inet6 xx:xx:xx:xx:xx:xx prefixlen xx scopeid 0x20<link> unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 100 (UNSPEC) RX packets 85482 bytes 118463837 (118.4 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 21444 bytes 1207429 (1.2 MB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

netstat

$ netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
0.0.0.0 xx.xx.xx.xxx 128.0.0.0 UG 0 0 0 tun0
0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 ens33
xx.xx.xx.xx 192.168.1.1 255.255.255.255 UGH 0 0 0 ens33
xx.xx.xx.xx 0.0.0.0 255.255.255.192 U 0 0 0 tun0
128.0.0.0 xx.xx.xx.xx 128.0.0.0 UG 0 0 0 tun0
172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0 docker0
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 ens33

Know someone who can answer? Share a link to this question via email, Twitter, or Facebook.