OSL Lounge [1,2] is the only one of the four lounges in Oslo (Gardermoen) Airport which allows passengers from non-member airlines (or any Norwegian Airlines passengers below Premium Flex) paid access for NOK350(/€35/US$40) from 3 hours before departure. (FYI: a) It is not a member of PremiumPass b) It is the only non-SAS lounge, and SAS lounges don't do paid-access to the general public c) (I had never heard of DragonPass but OSL Lounge is apparently available for US$50 on it ), but I only found out a month later).
At least so OSL Lounge says. However when I tried to pay to get into it recently (Wednesday July 3, 2019) they told me they were full that entire day so I couldn't. Not even "come back and try later". There was no sign reflecting that, and nothing on their website either. I asked them what days and times they tended to be unavailable, and they couldn't tell me, and didn't seem in the least bothered by that. (Yay, 8hr stopovers).
My question is: what days/times/months is OSL Lounge full/unavailable to paid-access passengers?