If you received a trademark specimen refusal from the USPTO stating the drawing does not match the specimen, it means the mark as shown in the specimen doesn't match the mark you originally filed in your trademark application.
Trademark drawing refers to the visual representation of your mark before the USPTO. A trademark specimen is a proof of how your trademark is used to label your goods/services in US commerce (e.g., a photo of your product bearing the mark). To prove your trademark's use in commerce, it has to show the exact mark you applied for. The only difference can be in colour - in the US, if you file a black-and-white version of your mark, it will protect all colour versions, so submitting a colour rendering of the same mark is ok. However, it has to be the exact same mark; no details can differ or be lost when colour is applied.
If you receive this type of refusal, sometimes, the examiner will allow you to change the drawing retroactively, but only if the differences between the marks are "not material". Most of the time, however, that won't be the case, and if that applies to you, you'll have to submit a substitute specimen. Applicants sometimes use various versions of their mark on their products/packaging/website, so they might be able to produce a new specimen showing the correct version of the mark. Other times, unfortunately, the only option left is to abandon the application and apply for a new trademark.
