Since downloading Aurora Store v 4.2.3 several days ago I have tried about a dozen times on different days to use it to install the Firefox app on my S4 without success.
I can't get the Aurora Store app to work.
I would be grateful for any help you could give me.
I ran into simmilar issues with aurora a while ago. From my understanding this is not related to LOS or MicroG. It's just Google blocking the anonymous accounts used by Aurora. What others suggested and I successfully implemented is creating a dummy google account with no personal info, and use it to with Aurora.
A few notes on this. If they ask for a phone number for verification use some online service and immediately add fallback options for login (like an authenticator app - i recommend Aegis). My account got blocked after a few day, but i successfully recovered it aferwardas. Can be a bit of a hassle to setup, but it's been working without issues since then.
Same on my LOS19. I flashed a complete new device with LOS and MicroG Pico and getting "rate limit" from the start.Thats been the same with a pixel 6a on calyxOS and brought me back to the play store now :/