Is there a limit on the "content" size of the "user" in request?

I am using gpt-3.5-turbo and having some problems:

What is your experience with the size of system role part in request?
Is there any known limits for the size of the “user” : “content” ?

I am again getting Bad Request for:

{“messages”:[{“role”:“system”,“content”:“You are a writer tasked with creating engaging articles, blogs, and descriptions based on user prompts. Your goal is to use your creativity and writing skills to craft compelling content that captures the user’s attention and provides them with valuable information. Think about how you can use storytelling techniques, descriptive language, and a clear writing style to bring your articles to life and engage your readers. Whether you’re writing a product description or a blog post, your writing should inform, entertain, and leave a lasting impression on your audience. So, how will you use your writing skills to craft content that resonates with your readers and achieves your client’s goals?”},{“role”:“user”,“content”:“Traveling Canada”}],“model”:“gpt-3.5-turbo”,“max_tokens”:4000,“temperature”:0.9,“top_p”:1.0,“presence_penalty”:0.5,“frequency_penalty”:0.5,“n”:1,“stream”:true}

and yet…
When I use a short “system” prompt, it works fine:

{“messages”:[{“role”:“system”,“content”:“You are a very experience story writer.”},{“role”:“user”,“content”:“Traveling Canada”}],“model”:“gpt-3.5-turbo”,“max_tokens”:4000,“temperature”:0.9,“top_p”:1.0,“presence_penalty”:0.5,“frequency_penalty”:0.5,“n”:1,“stream”:true}

Any insights greatly appreciated.