Can't send email from droplet to to some servers,others are OK

I’m using postfix and cyrus which I set up as directed with mixed results. Yahoo and Gmail handle my emails well. Hotmail put it in the spam folder but doesn’t after being notified it’s not span. I tested by reading maillog after an attempt to send mail from DOserver to my roadrunner email account and observing maillog. Here is the maillog entry: Jan 2 06:10:55 Hanksite postfix/smtp[20314]: 49C48609ED:,[]:25, delay=15, delays=0.02/0.01/15/0, dsn=4.5.4, status=deferred (host[] refused to talk to me: 554 5.5.4 Relaying denied. IP name lookup failed for myIPaddress)

It looks like they can’t get through my smtp port. Why don’t the other major servers have the problems ? How can I fix this?

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Hi, Problem solved with reverse DNS record. This is also known as a PTR record. Checked with support and P. Singh indicated that the PTR record is automatically set to the droplet name. You must therefore change the droplet name to your domain name.(i.e. To change the name of the droplet : Go to the control panel and select droplet. Then click on your droplet’s name. Next select Settings from the horizontal display of choices.(Ignore the Settings choice in the main vertical menu) Then select Rename and type in the new name.

If you’re new to DigitalOcean, they may be blocking Port 25. That’s pretty common and it’s a measure in place to prevent spam since the entry level is cheap (which spammers love).

To get that lifted, you’ll need to contact them via support ticket.

I have never set up any mail servers before, but anyway:

Do you have a reverse DNS entry so it is possible to look up the domain name from the IP?