Fetchmail not working

need help

$ fetchmail
29 messages for user@example.com at pop.example.com (454364 octets).
fetchmail: Connection errors for this poll:
name 0: connection to localhost:smtp [127.0.0.1/25] failed: Connection refused.
fetchmail: SMTP connect to localhost failed
fetchmail: SMTP transaction error while fetching from user@example.com@pop.example.com and delivering to SMTP host localhost
reading message user@example.com@pop.exampl.com:1 of 29 (12377 octets)fetchmail: Query status=10 (SMTP)
$ sudo systemctl start sendmail
Failed to start sendmail.service: Unit sendmail.service not found.
$ sudo swupd bundle-add postfix
$ sudo systemctl start postfix
$ fetchmail
29 messages for user@example.com at pop.example.com (454364 octets).
fetchmail: Connection errors for this poll:
name 0: connection to localhost:smtp [127.0.0.1/25] failed: Connection refused.
fetchmail: SMTP connect to localhost failed
fetchmail: SMTP transaction error while fetching from user@example.com@pop.example.com and delivering to SMTP host localhost
reading message user@example.com@pop.exampl.com:1 of 29 (12377 octets)fetchmail: Query status=10 (SMTP)
$ sudo systemctl status postfix
● postfix.service - Postfix Mail Transport Agent
     Loaded: loaded (/usr/lib/systemd/system/postfix.service; disabled; vendor preset: disabled)
     Active: activating (start-pre) since Sun 2022-02-13 14:32:08 EST; 1ms ago
Cntrl PID: 16487 (postsuper)
      Tasks: 1 (limit: 18836)
     Memory: 128.0K
     CGroup: /system.slice/postfix.service
             └─16487 /usr/sbin/postsuper -s

Feb 13 14:32:08 nekrins systemd[1]: Starting Postfix Mail Transport Agent...
Feb 13 14:32:08 nekrins postsuper[16487]: postsuper: fatal: open /etc/postfix/main.cf: No such file or directory
Feb 13 14:32:08 nekrins postfix/postsuper[16487]: fatal: open /etc/postfix/main.cf: No such file or directory
$ sudo touch /etc/postfix/main.conf
$ sudo touch /etc/postfix/master.cf
$ sudo systemctl restart postfix.service
$ fetchmail
29 messages for user@example.com at pop.example.com (454364 octets).
fetchmail: Connection errors for this poll:
name 0: connection to localhost:smtp [127.0.0.1/25] failed: Connection refused.
fetchmail: SMTP connect to localhost failed
fetchmail: SMTP transaction error while fetching from user@example.com@pop.example.com and delivering to SMTP host localhost
reading message user@example.com@pop.exampl.com:1 of 29 (12377 octets)fetchmail: Query status=10 (SMTP)
$ sudo systemctl status postfix.service 
● postfix.service - Postfix Mail Transport Agent
     Loaded: loaded (/usr/lib/systemd/system/postfix.service; disabled; vendor preset: disabled)
     Active: active (running) since Sun 2022-02-13 14:34:58 EST; 1s ago
    Process: 17201 ExecStartPre=/usr/sbin/postsuper -s (code=exited, status=1/FAILURE)
   Main PID: 17204 (postfix-script)
      Tasks: 2 (limit: 18836)
     Memory: 856.0K
     CGroup: /system.slice/postfix.service
             ├─17204 /bin/sh /usr/libexec/postfix/postfix-script start-fg
             └─17223 /usr/sbin/postlog -t postfix/postfix-script -p fatal Postfix integrity check "failed!"

Feb 13 14:34:57 nekrins systemd[1]: Starting Postfix Mail Transport Agent...
Feb 13 14:34:57 nekrins postsuper[17201]: postsuper: fatal: scan_dir_push: open directory bounce: No such file or directory
Feb 13 14:34:57 nekrins postfix/postsuper[17201]: fatal: scan_dir_push: open directory bounce: No such file or directory
Feb 13 14:34:58 nekrins systemd[1]: Started Postfix Mail Transport Agent.
Feb 13 14:34:58 nekrins postfix[17204]: Postfix is using backwards-compatible default settings
Feb 13 14:34:58 nekrins postfix[17204]: See http://www.postfix.org/COMPATIBILITY_README.html for details
Feb 13 14:34:58 nekrins postfix[17204]: To disable backwards compatibility use "postconf compatibility_level=3.6" and "postfix relo>
Feb 13 14:34:58 nekrins postfix[17216]: /usr/libexec/postfix/post-install: Error: /etc/postfix/postfix-files is not a file.
Feb 13 14:34:58 nekrins postfix/postfix-script[17222]: fatal: unable to create missing queue directories
Feb 13 14:34:59 nekrins postfix/postfix-script[17223]: fatal: Postfix integrity check failed!

FWIW - I haven’t played with postfix, but from Postfix Basic Configuration it looks like you might need more in the main.cf file than it just existing.

In /etc/postfix/main.cf you will have to set up a minimal number of configuration parameters