Openpaas incoming mail problem

I install openpaas on debian 9.
Public ip: 70.10.31.40
private ip: 192.168.10.37
mikrotik router: 192.168.10.1

Local domain mail all OK.
But Remode domain mail sending OK. Problem mail not income from any remote domain.
What is my wrong? Please help me.
Thanks

Dear Koli,
Could you explain more detail the issue ?
Which instructions installation do you follow ?

Thanks for reply.

I follow this guide to install.

https://docs.open-paas.org/getting-started/linux/
install success.

Logs:
cat /var/log/openpaas/error.log
2020/03/16 17:02:30 [error] 953#953: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 192.168.10.1, server: mail.example.com, request: “GET /api/authenticationtoken HTTP/1.1”, upstream: “http://127.0.0.1:8080/api/authenticationtoken”, host: “mail.example.com”, referrer: “http://mail.example.com/

cat /var/log/openpaas/james/error.log
2020/03/17 05:44:44 [error] 956#956: *15679 open() “/usr/share/nginx/html/robots.txt” failed (2: No such file or directory), client: 192.168.10.1, server: james.example.com, request: “GET /robots.txt HTTP/1.1”, host: “james.example.com
root@mail:~# cat /var/log/openpaas/james/error.log

mail out-going ok. Locally incoming ok. But not income mail from remote domain Like gmail, yahoo, etc,

I don’t find out problem. So I wish help.
Thanks

Do you know if you set up your MX record correctly on your DNS server? It could be that the external servers do not know where to send the email back to.