Im new to setting up a mail server and currently have the following errors.
Can anyone point me in the right direction?

from DNSstuff.com:

[Could not connect: Could not connect to mail server (connection refused by
remote mailserver).

My mail/warning log:
May 30 10:25:06 cochraneonline postfix/master[2884]: warning: process /usr/l
ib/postfix/smtpd pid 9372 exit status 1
May 30 10:25:06 cochraneonline postfix/master[2884]: warning: /usr/lib/postf
ix/smtpd: bad command startup -- throttling

mail/errors log:
May 30 10:27:07 cochraneonline postfix/smtpd[9394]: fatal: open dictionary:
need "type:name" form instead of: "virtual_mailbox_domains"

Is it my main.cf that is incorrect?
Thank you!

you have a syntax error in your main.cf where you specify virtual_mailbox_domains, i think. or actually maybe it means that you've deleted a return and have pulled the string "virtual_mailbox_domains" back up onto the previous line whichever parameter that is.

when i've seen those errors, then i have it set up that there is no relaying.
here's my config-

smtpd_banner = $mail_name
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
delay_warning_time = 4h

myorigin = $mydomain
mydomain = xxx.com
myhostname = prometheus.xxx.com
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
mydestination = xxx.com, prometheus.xxx.com, localhost.xxx.com, localhost
relayhost =
mynetworks = 127.0.0.0/8
mynetworks_style = host
mailbox_command =
mailbox_size_limit = 0
recipient_delimiter =
masquerade_domains = xxx.com
unknown_local_recipient_reject_code = 450
content_filter = smtp-amavis:[127.0.0.1]:10024
inet_interfaces = all

that might help some.
cheers.