I buy these almost every day, and suddenly this is unavailable to me. When I click the Get More AI Credits button from the Models tab in the Settings for Antigravity, I see this error.
Anyone else experiencing this issue?
Evidently they (Google) made changes to their system and failed to test things. 
Here is a link you can use to buy more credits.
I think Google doesn’t want us to keep buying credits. Instead, they’re pushing users toward their higher-tier subscription plans.
If you’re using Brave or a similar browser, you need to make sure that everything is enabled.
I am on chrome browser.