401 Error

What is HTTP 401 Error? 🔒🚫

🔹 HTTP 401 Unauthorized is an authentication error, meaning the request lacks valid authentication credentials to access a resource.

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1️⃣ Why Does 401 Error Occur?

✔ Missing authentication credentials (e.g., no API key or token).
✔ Invalid credentials (wrong username/password).
✔ Expired authentication token.
✔ Access denied due to insufficient permissions.

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2️⃣ Example of a 401 Error (REST API)

📌 Request Without Authentication

curl -X GET "https://api.example.com/user/profile"

✅ Response:

{
  "error": "401 Unauthorized",
  "message": "Authentication required"
}

👉 The server rejects the request because it needs authentication.

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3️⃣ Fixing 401 Unauthorized Error

🔹 Solution 1: Provide Correct Authentication

If using Basic Auth, include the username & password:

curl -u username:password -X GET "https://api.example.com/user/profile"

🔹 Solution 2: Add API Token or Bearer Token

If the API requires a token, include it in the Authorization header:

curl -H "Authorization: Bearer YOUR_ACCESS_TOKEN" -X GET "https://api.example.com/user/profile"

🔹 Solution 3: Check Token Expiry

🔹 If using OAuth tokens, refresh or regenerate the token before making requests.

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4️⃣ Difference Between 401 and 403

Error Code	Meaning	Key Difference
401 Unauthorized	Authentication is missing or incorrect	Can retry after providing valid credentials
403 Forbidden	Authentication is correct, but access is denied	No permission to access the resource

📌 Example:

• 401 → "You need to log in to access this resource."
• 403 → "You're logged in, but you don't have permission to view this page."

"HTTP 401 Unauthorized occurs when authentication is missing or incorrect. It means the server requires credentials before granting access. The error can be fixed by providing a valid username/password, API token, or refreshing an expired authentication token. Unlike 403 Forbidden, a 401 error suggests that authentication can be retried with valid credentials."