How To Fix 412 Precondition Failed

The Hypertext Transfer Protocol (HTTP) 412 Precondition Failed client error response code is used to indicate that the server is unable to fulfill the request because one or more preconditions specified in the request headers have not been met. This can happen in several situations, but the most common one is when a conditional request is made using a method other than GET or HEAD and the condition specified in the If-Unmodified-Since or If-None-Match headers is not met.

When a client sends a request with an If-Unmodified-Since header, it is indicating that the requested resource should only be returned if it has not been modified since the specified date and time. If the resource has been modified since that date and time, the server will return a 412 Precondition Failed response. Similarly, when a client sends a request with an If-None-Match header, it is indicating that the requested resource should only be returned if its entity-tag does not match the specified value. If the resource’s entity-tag does match the specified value, the server will return a 412 Precondition Failed response.

This error can also happen when a client is trying to upload or modify a resource and the Software Update Failed IOS 14 is unable to fulfill the request because the resource has been modified by another client since the client last retrieved it. This is also known as the “lost update problem” and it can be prevented by using the Prefer header which allows a client to retrieve the current state of the resource in case the local copy is outdated.

In summary, the HTTP 412 Precondition Failed error response is sent by the server when it is unable to fulfill a conditional request or when it detects that the resource has been modified by another client. This error can be caused by client or server issues, such as browser settings or problems with the server being accessed. To prevent this error, clients can use the Prefer header to retrieve the current state of the resource and avoid conflicts when multiple clients are making changes to the same resource.

Symptoms of Code 412 – Precondition Failed

Web mistake codes are otherwise called http status codes. There are five unique classes of http status codes and they generally start with the accompanying digits, contingent upon what sort of blunder was experienced by the client. These are likewise the symptoms of the mistake that the client is encountering. To make sense of further, here are the status codes.

4xx: Client Error

This mistake is sent back to the client when it is a client-side blunder. The client gets warnings of a terrible solicitation, content not found or unapproved admittance to the substance or something like that.

  • 400 – Terrible Solicitation
  • 401 – Unapproved
  • 402 – Installment Required
  • 403 – Illegal
  • 404 – Not Found
  • 405 – Strategy Not Permitted
  • 406 – Not Acknowledged
  • 407 – Intermediary Verification Required
  • 408 – Solicitation Break
  • 409 – Struggle
  • 410 – Gone
  • 411 – Length Required
  • 412 – Precondition Failed
  • 413 – Solicitation Substance Too Huge
  • 414 – Solicitation URI Too Lengthy
  • 415 – Unsupported Media Type
  • 416 – Solicitation Reach Not Fulfilled
  • 417 – Assumption Failed

412 Precondition Failed

Reasons for Precondition Failed – Blunder 412

4XX codes are brought about by the client or settings from the client’s side. The solicitation was not understood by the waiter due to wrong address bar section, inaccurate grammar, temperamental association or incorrect operating system.

Fix Techniques

There are specific investigating ventures for specific Web Mistake codes. However, there are likewise summed up fix techniques clients can perform when confronted with these sorts of mistakes.

In the event that a maintenance strategy works for you, if it’s not too much trouble, click the upvote button to one side of the response, this will tell different clients which fix technique is presently working the best.

Kindly note: Neither nor it’s authors guarantee liability regarding the consequences of the moves initiated from utilizing any of the maintenance techniques recorded on this page – you complete these means in spite of copious advice to the contrary.

Code references














Apache HttpComponents Center




412 Precondition Failed


The 412 Precondition Failed status code is a client mistake sent in light of a HTTP demand that isn’t of type HTTP strategy HEAD or HTTP technique GET, showing that one of the predetermined circumstances has failed and that the solicitation won’t be finished.

The most well-known reason for this blunder is the mod_security setting. This reaction will be sent by the mod_security module when any piece of the information mentioned over the web has the potential outcomes to be pernicious.

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