Not every immigration problem fits neatly into a standard category. You may have a visa refusal, an old overstay, a prior removal, inconsistent information in an earlier application, a criminal issue, a missed deadline, or a notice you do not understand.
This page is a starting point for people who know they have an immigration problem but are not yet sure what type of legal issue it is.
Keep notices, refusal sheets, prior filings, travel records, and information about earlier immigration events. The legal significance of an issue depends on the details; assumptions can make a later filing more difficult.