I just happen to come across this problem today. Thank God I woke up early on my own. I read through the chat and did some troubleshooting myself. I click on my alarm, click the time, try to choose an alarm sound and there is no sound for the preview. My default is the Bixby alarm. I also tried to select a ringtone, and that's when I got the error "unable to play during call". Clearly I'm not on a call but I remember making a call last night before bed. One on messenger and one on WhatsApp. So the phone probably got stuck on "call" mode somehow or the clock app detects my phone as if I'm still on a call. Hopefully the Devs could see this issue and possibly fix it. EDIT: After uploading the image by pressing the camera icon on this post, and choosing files, then selecting the screenshot, my alarm started working again. I also noticed my keyboard's sound is also finally turned on. If you're facing the same issue as me, I think a restart would do. Though I hope the Devs could look into this.
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