How to fix 'Send Later' function for immediate message delivery on iPhone 15?

Susan9 wrote:

Thanks so much. I *thought* I was in the right place; it is indeed iMessages that are sending immediately, even after applying “send later” criteria.

ive learned that this option is only from iPhone to iPhone, but it is still sending immediately. Any ideas or further suggestions? It’s conceivable that this relatively new phone is just wonky, as there are several glitches here & there, could that be?

The option isn't "only from iPhone to iPhone." The option is only available to people using iMessage. That can be someone with an iPhone, a Mac, or an iPad. It is also true that not everyone who uses iPhones uses iMessages. If an iPhone user isn't logged into iMessages, you can't use the Send Later feature.

I'm sorry, but I don't really use the Send Later feature as I can't figure out a reason I'd need to. So, I don't have a lot of experience.

Susan9 wrote:

I have tried everything except resetting the phone , mostly because I have already had to do that for other issues, and I’m increasingly frustrated; it is so time consuming.

You've posted in the Messages forum. However, it sounds as if you may really be asking about a feature of the Mail app? Is that the case? If so, I'll request this post be relocated.

What is the exact problem you're having? If you press and hold the send button, you should get the options to Send Now, Send at <some specific later time> or Send Later... Is that not what you're seeing? What are you seeing?