I’m late posting on this, so it’s probably too late to help, but it’s possible the employer is asking for the degree to be verified for equivalency. This is not the same as authentication - the official stamp that “proves” that a document is genuine and has really been issued by the appropriate authority in the home country (authentication should be done by TECO).
I don’t know for sure what it’s called in the US, but in Canada there’s a process called Educational Credential Assessment. You send your foreign credentials to one of the accredited organizations responsible for this and they send you back a document affirming that your education is equivalent to the Canadian degree of the same name. Or not, if they’re not happy with it.