Problems with the Spelljammer Mailing List server rejecting emails were reported back in December last year by Canageek.
A few days ago Michelle Brunes, the Operations Manager for the Wizards Community Team, posted bad news about the SJML (aka Spelljammer-L). The LISTSERV system, on their Oracle server is going to be turned off on the 15th of February.
This really is an end of an era. The Spelljammer Mailing List was set up back in September 1999. It has run for just over 14 years. Hundreds of Spelljammer fans (including myself) have hooked up with other fans on this mailing list, over that time.
Here is the full text of the announcement that has been posted to the SJML:
Hello! On February 15, 2015, Wizards of the Coast will terminate our LISTSERV system that manages this (and other) mailing lists. We've watched the usage of these mailing lists dwindle due to the rise of other communication platforms, such as forums and social media. Given this decreased usage, we have made the decision that it was time to turn them off. Please take these two weeks to back up or archive any emails you wish to keep. After February 15, 2015, they will no longer be available and these lists will cease to function. —Wizards of the Coast
It is not just the SJML that is closing down. 27 other Oracle mailing lists are also due to close on the same day. These include mailing lists for Al-Qadim, Alternity, Birthright, d20 Modern, Dark Sun, Dark Matter, Dragonlance, Eberron, Forgotten Realms, Gammaworld, Greyhawk, Mystara, Planescape, Ravenloft and Star Wars. Each of those mailing lists also has hundreds of subscribers.
I have been trying to spread the word to various other RPG communities who have been served by these mailing lists, in the hope that someone within each community will be able to save a copy of each mailing list and get an archive put up on an appropriate fansite.
Sharing this post (or the information it contains) could help make a difference.