What was happening in the church of Smyrna?

Revelation 2:9 (ESV)

9 “‘I know your tribulation and your poverty ( but you are rich) and the slander of those who say that they are Jews and are not, but are a synagogue of Satan.

Jesus is fully aware of what the Smyrna congregation was experiencing, as is clear from the word I know. (How could it be otherwise, since Jesus was among the seven lampstands, i.e., the churches (Revelation 2:1)?) This church was experiencing tribulation and poverty and slander.