Schaduling doesn't work properly
I have made a schedule post for 11:53 AM. But it was not published at all. It is still in the scheduled statuses.

I guess there is an issue with timezone. Is it so? I wait for it to be published and see if there is any specific time difference or not.
I just tested it (I'm on the Canadian east-coast) and the scheduled status was published at the right time BUT the scheduled panel didn't refresh properly, is it the same behavior on your side?
I noticed that scheduling from server side doesn't work properly for all instances. They still appear like scheduled but were never sent. Tested on fediplan or Fedilab scheduling (server side). I tested on an instance where it fails each time and it was not related to the timezone.
I have no issue with scheduling on Fedilab.
Did you pick up server side too on Fedilab?
I think I do it from device. If Sengi does scheduling from server side, I will try it on Fedilab to see the result
Yes, Sengi is using the server side's scheduling, I wasn't aware that some instance might be problematic... :/
Then perhaps we need to show the option if scheduling is allowed by the instance.
Unfortunately, there is no way to know it. I think that's a server side configuration. I didn't investigate much more (ask the admins or check the doc about what is needed to make it work).