Is It A Violation to Link to an Old Answer?

no it is not a violation..

No, it is not a violation to link to an old answer.

The link is not a violation unless:

1. The link goes nowhere or to a deleted post.

2. The post at the end of the link is a violation (like linking to a racist post).

So if your link was ok, there must have been another source of the violation.

I am guessing that you did not answer the question other then to add the link to another answer/question. If this is the case then you were probably reported for point gaming, trying to earn two points by not answering the question and just supplying a link to something else.

If you did answer the question correctly and then added a link, it is possible that there might have been a problem with the link question/answer and it was reported. but offhand I cannot see why.

It probably was not a violation, but may have been reported (in error) as a callout.

Anytime you link to another user's question in your answer, you run the risk of being reported for calling out another user. It's not actually a callout unless you link to (or post the content of) another user's question (or answer) for the purpose of drawing negative attention to that question (or answer), but some consider any link to or re-posting of what another asks or answers to be fair game for reporting.

it depends on whether you actually answered the question. For example:

Question: "How long should I bake a 17 pound turkey?"

Answer: "I already answered that question a year ago. Read my answer here: [link]

That above example would be a non-answer violation.