I got the same email.
On the dashboard, it says this:
This App has violated Twitter Rules and policies. As a result, it can no longer be accessed. For assistance, submit a support ticket.
With no more info.
As for their current plans, here’re the cheapest ones:
Free
For write-only use cases and testing the Twitter API
- Low rate-limit access to v2 tweet posting and media upload endpoints
- 1,500 Tweets per month - posting limit at the app level
- 1 app ID
- Login with Twitter
- Cost: Free
Basic
For hobbyists or prototypes
- Low-rate limit access to suite of v2 endpoints
- 3,000 Tweets per month - posting limit at the user level
- 50,000 Tweets per month - posting limit at the app level
- 10,000/month Tweets read-limit rate cap
- 2 app IDs
- Login with Twitter
- Cost: $100 per month
Indeed, it seems that if we can log in with the free plan, we can’t get tweets info (no more embedding).