I know it's advisable to look for the publishers instructions on how they would prefer you to follow up on a submitted manuscript. However, the publisher that currently has mine is no longer taking submissions, and has taken all that sort of info off their website. What's the best way to follow up if you're not sure what they would rather have you do? Thanks.I think I know who you mean because I regularly visit the websites of all the LDS publishers and I noticed that happening very recently on one site. I haven't heard any industry gossip so understand that what I'm about to say may be way off base.
If they've suddenly stopped taking submissions, they're most likely in trouble or are going through some restructuring and need some breathing space.
Do you have an e-mail address for the submissions editor? If so, that's the easiest and (in my opinion) least intrusive way to contact them. Send a short polite e-mail asking the status of your submission. You can mention the change in their website and express curiosity if you want, or not. Give them a couple of days to respond because if they are struggling, they may be understaffed.
You can also send a letter asking the same thing. If you write, give them two weeks to respond.
Or you could call. This is the last option I'd advise because if they're way past the time when they should have responded, it probably means they're swamped in the day-to-day business of staying alive.
In any case, if you e-mail, snail mail or call and you don't get a response within 30 days, you can probably safely assume that your manuscript has been rejected.
I'm sorry I can't be more definitive on this. As I said, this is my best guess on what is happening, but I could be completely wrong.