TLV based DM, Fly about 15 TLV-JFK trips/year.
always for business, always booked by company agent. Unfortunately, my company doesn’t pay for business class, so I try and use a mix of GUCs and miles/cash to upgrade- using the app or website upsale functionality. Last 3-4 trips, it’s just “blocked” (shows open seats , but giving me a message like “you’ve chosen the delta comfort+ experience…” )

Chat/phone supports says “it’s sold out” or “not upgrade eligible”. Have a strong feeling the corporate reservation causes this “glitch” - anyone has similar experience?