Fix Pinterest error (code: 429)
The error: "Pinterest error (code: 429) with message: You have exceeded your rate limit..." states that you have reached the Pinterest rate limit for the app.
To fix this error, try increasing the time between shared posts, as posting too often to Pinterest will hit the rate limit.
If you're sharing more than one post then reducing the number would also help in this case.
10 API calls are allowed by Pinterest within an hour. 1 shared post does not necessarily mean 1 API call since it may take more than one API call to actually create your post on Pinterest.
The best way to avoid getting this error is by increasing the time between your posts so that Revive Old Posts is sharing at most 2-3 times to Pinterest within an hour.