(Bangkok) My husband is on his 1-year Non-B visa extension. His latest arrival into Thailand was August 8, 2023 after which the extensions were processed. The TM.47 slip on his passport says he's due to report March 4, 2024. We tried to register his first ever 90-day online report but it got rejected with the message to just contact local immigration. (Oh well, worth a try.) I read that it can also be done by an authorized person. Do we just write a standard authorization letter?

Many thanks in advance.