The COE process involves the government conducting a deep background check. Immigration meticulously verifies all your documents, assesses the financial sponsor's stability (for students), or the sponsoring company's legitimacy (for SSW). This thorough verification process naturally requires a significant amount of time.

Even minor errors, such as a misspelled name, an incorrect date, or inconsistent addresses, can lead to rejection. Immigration views such discrepancies as a sign of either carelessness or a deliberate attempt to mislead. It is vital to double-check every entry against your passport and official documents.

Immediate appeals are rarely successful. If your application is rejected, you must first identify and address the likely cause (e.g., provide stronger financial proof, resolve document conflicts). Generally, you cannot reapply for the same purpose within six months, unless you can demonstrate a significant positive change in your circumstances.