Yes on extension of stay as retiree. For some reason my 90 days report was rejected for "incomplete address" and they told me to come in person. No idea why. I did the TM30 myself and I know my address!! It's a bit of a pain because I had other plans with my day. Thanks again.
If your online application was rejected (for reasons like 'incomplete address'), you still can use the 7 days grace period for in-person application at the Immigration office. That is 100% sure.
But you are right, you cannot do it online after the 90-day date.
I applied through the website but my submission was twice rejected for "incomplete address". Not clear why (always use the same as in the TM30).
I will thus have to go in person (also because I am now in the 7 day grace period). Which office does this nowadays: ChaengWattana Immigration Building B or Muang Thon Thani? Thank you!