[ealgeone]

So in 1898 he joined the Capuchin Franciscans in Detroit and after struggling through his studies, in 1904 was ordained a “sacerdos simplex” - a priest who can say Mass, but not publicly preach or hear confessions.

What is the reason for this?

[Joe 6-pack]

I had to look it up but this is what I found:

"On 24 July 1904, Solanus Casey was ordained to the priesthood by Archbishop Sebastian Messmer at the St. Francis of Assisi Church in Milwaukee, Wisconsin. He will be ordained a “sacerdotus simplex” or “Mass Priest” which prevented him from hearing confessions or preaching doctrinal sermons because of a judgment that he had not performed sufficiently well in his seminary classes. Indeed, Fr. Casey had great difficulty in seminary as most of the classes were in German, with which he was not very familiar."