Are you working on a computer or a phone?
Is it possible that when you have difficulty that it's a blip due to one of the many variables in play, Etsy, brower, internet ... I do have blips when working on my computer with Etsy, but with other things too. When things aren't working normally I do a clear cookies, roboot, make sure my brower is up-to-date, reset my wifi modem. And things go back to normal. It seems to me that working with computers results in virtual clutter and clearing that from time to time helps. And I think sometimes the internet itself, the brower and Etsy has blips.
Another possibility is that you may need to wait for something to happen on Etsy, eg. the payment processing to complete, the transaction to synch up, etc. If you are get a sale and don't seem to be able to purchase a label right away, try waiting an hour or two and then try again.
