Facing error during creation of tickets through API's

Welcome to the Atlassian developer community @ChetanKrishnaSaiNaid,

There’s not a lot of context to go on. Next time, maybe have a look at our community guidelines on How To Ask A Good Question ❓. Meanwhile, the one clue we can see in the response is the HTTP status 429, which indicates too many API requests. You might start with the documentation on rate limiting.