First, the entire notion of sitting embassies that this implies did not exist in that era. To say that one exchanged embassies is to say that envoys were sent from one court to another.
Second, nothing in that article suggests that a Chinese 'ambassador' got any further than Seleucid Syria, during the Hellenistic Era, before the Roman Empire even existed.
Third, that Roman merchants made is far as China - and vice versa - is hardly controversial. But to suggest that they were 'officially' dispatched by, say, Marcus Aurelius is rather pushing it.
Fourth, and related, there is no record of Marcus Aurelius sending envoys to China. At best, one would say that this was of no consequence.
Fifth, the Roman Limes were mostly in place some fifty years before the reign of Marcus Aurelius, and almost entirely completed during the reign of Hadrian.
Sixth, the uncontroversial notion that some itinerant Romans stumbled their way over to China hardly leads to the idea that said Romans toured the rudimentary Chinese frontier defenses of that era, returned to Rome, received an imperial audience, and led, say, Emperor Trajan to say: A ha! What a wonderful idea! We shall mimic it post haste!
Seventh, it is well-known that the Romans had a dim concept of some great empire on the other side of the world, as did the Chinese have a dim concept of some great empire on the other side of the world. There are plenty of cartographic and geographic records to confirm that this is all they were aware of. Over and over again there is nothing whatsoever of detail or substance written in either Rome with regard to China or in China with regard to Rome. All it ever amounts to is: there's some great empire way over there, beyond all these other great empires that are of far more immediate interest.