Created attachment 109692 [details] the photo opensuse 42.3 kde apps 17.12.0 kde frameworks 5.41.0 kde plasma 5.11.5 smtp.free.fr i composed a mail with a joined photo (2.2 Mio) then i send it then i get a message Failed to transport message. server connection interrupted. there is no explaination if i use my smartphone to send same mail there is no problem.
fixed in 5.7.1
sorry i selected kaddressbook it is obviously a report about kmail