TL;DR:Request a written reason from the issuing office, then either file a formal reconsideration quickly (assume 1–2 weeks) or reapply with stronger, corrected documentation; consult the embassy/immigration bureau or a licensed lawyer if unclear.
Read the refusal notice immediately and contact the office that handled your application (embassy/consulate or immigration office) to request a written reason and the procedure for reconsideration. If the notice gives no timeframe, assume a 1–2 week window to ask for reconsideration and act fast. Then do exactly one of the following:
- File a formal petition/reconsideration with new, specific evidence addressing likely defects (financial proof, return ticket, clear itinerary, sponsorship letters, certified translations).
- Or withdraw and reapply after you correct weaknesses; submit stronger documentation and a short cover letter explaining what changed.
Document every contact, keep copies, and do not rely on unofficial “fixers.” If the reason remains unclear or your case is complex, engage a licensed Thai immigration lawyer or a reputable visa consultant to review and submit the petition. For contact and procedural details, consult the Thai Embassy visa FAQ and the Royal Thai Immigration Bureau websites (thaiembassy.org; immigration.go.th).
Answer will be updated soon