Ok. Update for others that are struggling. I contacted LastPass tech support. Was trying phone several times and never hear my phone ring. Apparently I needed to turn of spam call blocking for it to eventually come thru. My setup was a business account that had a policy to force all users to use MFA. The new console wasn't letting me add myself as an exception to the policy, but the old console did. Once I was in the exception list, then I went to my own account settings and disabled MFA for me. After that, I tested logging in without need of MFA. Once that was confirmed. I did a backup (in settings) of my Authenticator App (because I had other accounts tied to it). Then deleted the App. Re-installed. Then basically reverse steps of adding MFA back in and re-pairing it. I renamed the old pairings first just in case. Hope this helps someone else.
This is in Response to Measpaz post on the 1st page and Amazon 2FA. I could seem to get my reply to show up right after his name but I want to say thank you to him and give him credit for resolving LP Authenticator and Amazon Push Notifications. This has driven me crazy for over a year and a half now but thanks to this post I got it figured out. Last year when this happened I was using Last Pass and Last Pass Authenticator but this year I switched to 1Password because they gave it to me for 50% off basically 1.50 a month for 12 months. I thought perhaps because I started using 1 Password on my phone also it was clashing somehow with LastPass authenticator. I was signing into LastPass in a new Tab on Windows PC and Macbook Pro verifying on my phone as trusted enabling disabling the Authenticator setting in the Account Settings. Then after seeing this exact post about having to be signed through the "Last Pass chrome extension" and not just in another tab did it finally work. It seems you only get the push notification when the Last Pass Tab extension is turned on. I have also disabled and re-enabled 2fa settings at Amazon probably 25 times. This is so strange and the same thing happened when I tried it on my MacBook Pro in Safari no push but it's because Safari does not off the Last Pass extension, but using Chrome on my Macbook with the extension running it sends the push notifications. If I disable the Extension on either my Windows PC (Which I Did because I switched to 1 Password and I didn't want both extensions prompting me on every site I use 2FA) then I would not get the Push Notification on either my old iPhone or my New Samsung S22 Ultra. I want to thank the author of this reply it saved me from the insane asylum. Just make sure you click that little LastPass Box coming from the Last Pass Extension when it says it will handle it.
I deleted the Authenticator app (after doing a cloud backup) and I re-enrolled my Pixel phone with 2FA via Lastpass -> Account Settings. In that process, I landed on a screen that showed my Samsung Tablet as being the "Primary" 2FA device. I suspect the Authenticator push-notifications were going there. After enrolling, the pixel phone shows as primary and I am getting the Push Notifications again. I wish I had screenshotted that page as I cannot get back to it and I do not want to re-enroll again.
This whole 2FA enrollment flow is incredibly buggy and requires multiple re-logins on phone and desktop. I wish LastPass would spend some time QA-ing their products.