Notarized marriage certificate required for ED visa?

My son is enrolled at a kindergarten in Chiang Mai and we’re awaiting his ED visa and just learned we need “Parent’s marriage certificate notarized by the Embassy of England for authentication” and I’m confused on how to get this if not in England (and on a time crunch), and also why it’s needed.

We applied online to the DC embassy and already submitted our original marriage license.

I’m wondering what the paperwork would be if we weren’t married (like how is that relevant? 🙄)

He and my husband (a naturalized US citizen) are applying on US passports, but we were married in Scotland.

Also, if it gets approved while there, can we enter on it the next time we leave as long as it’s within 90 days of it being issued?

I have a question regarding my non-immigrant B (teacher) visa. My employer just contacted me to find out if I have had my documentation (degree, transcripts, TOEIC score, etc.) verified by my embassy. Has anyone else had any experience with this, or is it just my employer confusing things? Thanks in advance.

I've just been informed by immigration that for a TYPE-0 visa application my British passport has to be authenticated by the British Embassy otherwise the application for TYPE-0 based on Thai Spouse will be rejected? I've not seen this posted anywhere on this site.. anyone had to do this also?

Dependant Non imi O extention:

We have a marriage licence from Gibraltar in english with an apostille from Gibraltar.

We also have the international birth certificate

from Spain for our daughter with an apostille from Spain.

But we were just told by HR that we need to get those documents certified by the embassys of each country here.

Which makes no sense cause they already have been certified in each country!

Is this still true?