Good afternoon. Just completed setting up my Mailinabox with two domains and running. Just followed the youtube tutorial having my domain registered in gandi.net and digitalocean.com.
Whe I began sending email, everyone sent to microsoft accounts (outlook, hotmail…) is returned back with a message Unfortunately, messages from [134.122.xx.xxx] weren’t sent. Please contact
your Internet service provider since part of their network is on our block
list (S3140)
After logging in mxtoolbox.com, I find the trouble is the address belongs to a group that is is listed by UCEPROTECTL2 and UCEPROTECTL3
Have a search for UCEPROTECTL3 on this forum. I have the same kind of set up with Digital Ocean. Generally no problems but Microsoft can be difficult. There are other posts where the procedure for dealing with MS is set out.
Also look at the install and maintenance instructions for tools to help you check your setup. Mxtools helpful from memory.
I went through the same thing with Digital Ocean. I ended up moving to Linode and have had much better luck. And, I got two free months again. You need a sponsor link though. Here’s one if you need it: linode.com/syntax. It’s from the Syntax podcast with Wes Bos and Scott Tolinski. I’m sure that’s the last thing you want to do, but it worked out much better for me. You need to tell them you are hosting a mail server and they will make tweaks on their end to allow it to work. There were a couple of issues with IPv6 getting blocked but they quickly and happily made changes on their end to make that work as well. The few times they’ve ended up on UCEPROTECT they have gotten off of it rather quickly. I don’t think I’ve ever seen DigitalOcean not on it.
As for your specific problem: I don’t think UCEPROTECTL is your issue. It may be indicative of whats happening, but I don’t think many places reference it, particularly level three. MX-Toolbox only takes of 1% reputation if you are on it. My mail server has been on level 3 for a couple of weeks and Microsoft is working fine. I think MS has their own internal database which is why you have to work through them to get off their list.
I am on Linode too. They have email ports blocked by default. You have to submit a support ticket and ask for the email ports to be opened up and it’s not a problem.
I ran into an issue with IVP6 addresses assigned by SLAAC. Summitted another support ticket and I got a dedicated range so I could assign a permanent IVP6 address for my server. I had problems with a European server that was rejecting my mail because of the SLAAC address.