Paul, an apostle of Jesus Christ by the will of God, and Timothy our brother, unto the church of God which is at Corinth, with all the saints which are in all Achaia:
2 Corinthians 2:1
"2 Corinthians is written to the assembly that was founded on Paul’s first visit to that city. Since his
departure and subsequent ministry in Ephesus, the apostle has learned a great deal about the serious problems fermenting in this assembly. Problems with worldliness, internal wrangling’s, and doctrinal defections continue to fester in spite of Paul’s efforts in the first epistle.
BooksOfTheBible
2 Corinthians 2:1
"2 Corinthians is written to the assembly that was founded on Paul’s first visit to that city. Since his
Opposition to Paul’s ministry continues to mount, especially coming from the party that associated itself with Christ (compare 10:7; 11:13). The leader of this group seems to have been especially hostile to the apostle (10:7-11).
2 Corinthians was written after he left Ephesus, the most likely date for 2 Corinthians is late A.D. 55 or very early A.D. 56."