How to configure port 465 for my internal email server as environment variable

My newly deployed web app seems stuck at email service port as the server keeps complaining null value of it and thus preventing other access to api requests. Please correct my config or point out what I have missed other than this config to get email configuration work.

here is my service config:

[Unit]
Description=Kestrel service running on Ubuntu 20.04
[Service]
WorkingDirectory=/var/mydir
ExecStart=/usr/bin/dotnet /var/myfolder/API.dll
Restart=always
RestartSec=10
SyslogIdentifier=myidentifier
User=www-data
Environment=ASPNETCORE_ENVIRONMENT=Production
Environment='Token__Key=OKOKOKOKOK'
Environment='Token__Issuer=http://myIp'
Environment='EmailConfiguration__From=myEmail;SmtpServer=smtp.ionos.com;Port=465;Username=myEmail;Password=myPW'
[Install]
WantedBy=multi-user.target

Besides, I tried allow firewall as below: sudo ufw allow 465/tcp

Using netstate -ntpl, I didn’t see 465 is listed Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 127.0.0.1:5000 0.0.0.0:* LISTEN 77669/dotnet tcp 0 0 0.0.0.0:6379 0.0.0.0:* LISTEN 40751/docker-proxy tcp 0 0 127.0.0.1:44879 0.0.0.0:* LISTEN 7207/containerd tcp 0 0 0.0.0.0:8080 0.0.0.0:* LISTEN 80693/docker-proxy tcp 0 0 0.0.0.0:8081 0.0.0.0:* LISTEN 31727/docker-proxy tcp 0 0 127.0.0.53:53 0.0.0.0:* LISTEN 19179/systemd-resol tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 18860/sshd: /usr/sb tcp 0 0 0.0.0.0:5432 0.0.0.0:* LISTEN 37713/docker-proxy tcp6 0 0 ::1:5000 :::* LISTEN 67679/dotnet tcp6 0 0 :::6379 :::* LISTEN 60755/docker-proxy tcp6 0 0 :::80 :::* LISTEN 33532/apache2 tcp6 0 0 :::8080 :::* LISTEN 50700/docker-proxy tcp6 0 0 :::8081 :::* LISTEN 37035/docker-proxy tcp6 0 0 :::22 :::* LISTEN 17860/sshd: /usr/sb tcp6 0 0 :::5432 :::* LISTEN 37719/docker-proxy