I don't know if this is a common occurrence or what, but I've been having severe problems booking partner award tickets on AS.com.

Example:
I had an open-jaw I wanted to do:

DTW-GTF (4/16)
SMF-DTW (4/25)

Numerous options popped-up. I was at 24K and sprang for the $29.32 to buy up to 25K and then tried to book the award. Got all the way to the final booking page, but once I hit submit, it came back with an error and said to try again. Of course, an hour later, a day later the same problem. It finally struck me to check DL.com/NWA.com and the flights were not available at all for award redemption. However, there were other flights at less than ideal times that were. I went back to AS.com, tried to book. Again, same error. Code "1990".

So I decided to finally call AS. They said website was wrong, no availability at all on 4/25....

Furthermore, they refused to do anything about the $29.32 I paid since it's a non-reversible transaction. Seems dubious to me considering

1) The shown award availability that prompted me to buy the miles was wrong (and it's not like an award was sold out, it was never there)
2) The award availability does exist but AS can't seem to get a hold of it. So the award really is there, they just don't want to let me book it.

In the end, I just used some DL miles... but this is really strange, and seems especially strange that even phone agents aren't seeing correct availability.