https://jlssolutions.com/qa/408558/usps-check-is-not-working?show=419229#c419229
USPS has stopped providing this service for free and now only allows limited lookups. We’ve added it for tuition at our cost through a paid provider, but not for fundraising.
These providers are very expensive. For example, one charges about $0.05 per lookup, and even then limits you to only 1 lookup per second Zyla Labs ZIP Code Locator API
https://zylalabs.com/api-marketplace/data/zip+code+locator+api/5462#pricing
We are considering adding this as a paid option for fundraising as well, and pass thru the fee.
