This came up because of the interesting Taylor DeSoto Youtube.
Good talk, many interesting points. Servertus, who was at Valladolid in 1527 as a teenager, secretary to Juan de Quintana, accepted the heavenly witnesses verse as scripture. Grantley McDonald in: Raising the Ghost of Arius p. 152-154 https://openaccess.leidenuniv.nl/handle/1887/16486 seems to be ok in that section and gives Latin paragraphs. (You imply Servetus as a contra at 8:50.) Offhand, I do not know of Erasmus-Servetus correspondence. Good info here on Erasmus and Servetus, p. 36-39, should be visible. Encounters with a Radical Erasmus: Erasmus' Work as a Source of Radical Thought in Early Modern Europe (2008) Peter G. Bietenholz https://books.google.com/books?id=1cxY0mm2ZwMC&pg=PA36
When Servet discovered that Erasmus had left Basel, he followed him to Freiburg to present him with a copy of his book, but Erasmus refused to receive him.11
11 Bataillon 1937, 462; Gauss 1966, 417–434; Gilly 1985, 288; Bietenholz 2008, 35–39
In Bietenholz there is an indirect evidence of Erasmus not receiving Servetus. The four refs can be checked.
By 1530 the young Spaniard had arrived in Basel in search of a publisher for his book and, as we shall see, of Erasmus himself. ...
Whether Erasmus ever read much of De Trinitatis erroribus may be doubted. What is certain is that Servetus would have liked him to. When he arrived in Basel in July 1530 he may have been disappointed to find that Erasmus had left for Freiburg. So it was thither that Servetus travelled to present Erasmus with a copy of the newly printed book, but the latter apparently 'would not lend him an ear.' In a letter to the Strasbourg reformer Martin Bucer he referred to what can only be Servetus' De Trinitatis erroribus. He had been told, he wrote, that the book was printed in Strasbourg with the wholesale approval of Wolfgang Capito, indeed, that Oecolampadius would permit a new edition in Basel if a few corrections were made.18 To suggest that the reformers of Strasbourg and Basel sympathized with Servetus' ideas was malicious, but not entirely unfounded. The brilliant young Spaniard had encountered much encouragement in the Rhenish cities. Martin Borrhaus and Wolfgang Capito, who befriended him, were not only staunch Erasmians but also casual strayers from the path of orthodoxy
... In seeking contact with Erasmus, Servetus likely expected him also to acquiesce with the cogency of his arguments.