Not able to delete/trash posts

When I log into my website’s wp-admin panel, I don’t see the Trash option under the post names anymore. (I used to get that option earlier.)

Please note that, I still get the same option
– for my site pages
– and even for my post drafts (so I can delete my posts by switching them to draft first, which is sort of tedious)

Even when I try out the bulk action Move to Trash (which is somehow still visible in the drop-down), I am redirected to a page with nothing but a simple message:

Sorry, you are not allowed to move this item to the Trash.

Kindly suggest what could be done.