Bizare postfix problems with file ownership

[lazacom]

I had problem with non working postfix server (after unsucessfuly completed ISPConfig installation) and I solved it with removing it (yum remove postfix) and installing it from source (postfix 2.9.4, built as root).

I had to install 2.7 or newer because virtualmin forced me. After that, mail server started to send test email and could get it.

But, after that, I noticed that I can receive outside emails but can not send mails to any other domain (only to other emails on my domain, nemogucamisija.com). Error code was:

Out: 220 nemogucamisija.com ESMTP Postfix
In: EHLO mail-bk0-f46.google.com
Out: 250-nemogucamisija.com
Out: 250-PIPELINING
Out: 250-SIZE 10240000
Out: 250-VRFY
Out: 250-ETRN
Out: 250-STARTTLS
Out: 250-AUTH PLAIN LOGIN
Out: 250-AUTH=PLAIN LOGIN
Out: 250-ENHANCEDSTATUSCODES
Out: 250-8BITMIME
Out: 250 DSN
In: STARTTLS
Out: 454 4.7.0 TLS not available due to local problem
In: QUIT
Out: 221 2.0.0 Bye

Then I noticed that postfix can not access certificate. Disabled TLS but now I can not set Transport Mapping, cause postfix can not access /etc/postfix/transport . Tried

chown postfixostfix /etc/postfix/transport
chmod 777 /etc/postfix/transport

and

postmap /etc/postfix/transport
postmap: fatal: open database /etc/postfix/transport.db: Permission denied

I know building it as a root was not smartest idea, but tutorial required it. So, what I shoul do to fix this? Or, any other solution to enable sending emails to other domains than my own?

Thanks in advance!