Hello Aaron,
Sorry for the trouble there. Let’s tackle the not found error first. Most of the time when you have one of those in WordPress for something you know is there, the permalinks need to be saved again. Go to the settings section in your WordPress control panel and choose permalinks. Choose one of the options other than the default. I would suggest the post name option. Then scroll down to the bottom and save your changes. Even if you’ve already selected post name, go on and save the options. When you save these, it clears out the permalink cache and hopefully that will let things be found like they should be.
For the audio, it looks like the “attachment page” has been picked up instead of the actual file. When you’re uploading the file in the pop-up box, there is a field labeled link URL. Click on the one that says “File URL” before you “use as message audio” button and save your changes.
To double check that it did the correct thing, you’ll notice a URL in the field for the message audio file. Make sure that ends in the file name of the file you uploaded, something like message.mp3
Let me know if either of those doesn’t get things on track for you.
Thanks,
Bill