Found a solution thx to Yil for an old post
open ioftpd.ini
scroll down to
# limit encryption to a particular type: SSL2, SSL3, TLS
# leave this undefined to support any of them
;Encryption_Protocol = SSL3
comment Encryption_Protocol so it supports all encryptions
save and restart ioftpd
PS. old post can be found here:
https://oss.azurewebsites.net/forum/archiv...p/t-13223.html