I had unusually had my 90-Day online application rejected so I went into Chaeng Wattana to do it in person. I was told the reason for the rejection was that I should have chosen Wattana for the City/Amphur. Today I checked the online 90-Day form and saw that Wattana it isn't one of the options in the drop down box. Since 2013 I've been using:
City/Amphur: Khlong Toei
District/Tambon: Khlong Toei
... and it has never been rejected before. Puzzled!
TLDR : Answer Summary
The user experienced a rejection of their 90-Day visa application online due to a city/amphur discrepancy. Despite using Khlong Toei for years, Wattana wasn't listed in the online dropdown. Comments suggest double-checking the exact address and considering alternatives like Vadhana, reflecting a home address that may not exactly match any of the common names listed.