Flying on a flex fare tomorrow. Was able to select seats for all my flights tomorrow, but when I pressed confirm, an error message in red (ref 6016) tells me that "We were unable to assign a seat for the following travelers.".

Flight 1 and 3 seat selections were confirmed, but flight #2 would not stick and that seat remains at the rear 1/3 of the plane (I had chosen this seat originally at time of booking when the schedule had allowed a lengthier connection).

I have to dash from the A20s at YYC to the D80s. 12 minute walk, according to the website, or a 5-minute drive on the link shuttle. I have 2 legs, so I am walking.

Are there any reasons as to why I cannot confirm the changes?

Thanks for any insight you can provide.

**Looked at EF and some seats are blocked by an "X" and others show as occupied, but the AC seat selection tool shows the seats as open, so I don't know. If it means anything, EF numbers are: J1 C0 D0 Z0 P0 R0 Y6 B0 M0 U0 H0 Q0 V0 W0 G0 S0 T0 L0 A0 K0 F0**