I'm trying to book an appointment to convert my foreign license into a Thai one at one of the Bangkok locations via the online system at https://gecc.dlt.go.th. When I go to the date selector, even though some dates have a green number indicating there are slots, I get this error message:

I don't know if this relates to my overseas license validity period because on a previous screen they asked what year it expires (only going up to 2032, which my license actually expires even later) and it's just a bad translation?

It seems at the bottom to tell me to "reserve the queue for 1 ticket instead" - notably I have a motorcycle and car license on the same physical card - but I just can't figure out what to do here to get an appointment. Do I write my expiry date as being within 180 days, do I only do one license at a time, or do I skip this system entirely and either call or drop in?

I used to just drop in at the DLT office at Bang Chak to get an IDP. I once went in the morning and was told to come back at 2 pm when they would accept walk-ins. Each office may be different, but it would not hurt to visit in person and ask. Take all of your documents with you in case they agree to help you on the spot.

You can get past the error message (which should really only appear if applying for a renewal) if you select "lost driving license". You can then go on to select a date and time. What actually happens when you show up for the appointment is anyone's guess.

Edited 13 minutes ago13 min by Upnotover