Issue purchasing trading cards lol

[Goober]

I have steam up in a web browser, mobile web browser, mobile app, and steam proper. All of these are authorized devices. I'm literally trying to spend $0.26 on some Bloons TD trading cards so I can complete the set and craft a badge.

After clicking purchase, I'm redirected to a page that says I must confirm the purchase on the mobile app. I go into confirmations on mobile and see the transaction that is pending. I indicate that it is me making this purchase, and hit confirm. The transaction disappears from the "confirmations" list, but the original purchase page (as stated, on Steam itself or in a browser) never updates. So it just sits there forever, awaiting my mobile confirmation (which has already been confirmed)

I'm not exactly new to steam, but I'm failing to jump through these hoops. I just want those cards >.<

[i like you]

It might not be the same for you but I had this exact issue just 2 days ago. In my case, after confirming in the Steam app on phone it kept me in this loop and I simply gave up (closed the page, just went on doing something else) for like give or take 20 minutes after which I tried again and it let me buy cards without issue.
I'm sorry that it's all I've got for you, the auth seems a little buggy recently but I hope you do find a way to deal with it.

[Goober]

Yeah really all I had to do was wait, and then I did try purchasing only one card at a time and then things started to work. Thanks for your help