The Outgoing server (SMTP) %S does not seem to support encrypted passwords. If you just set up the account, try changing the 'Authentication method' in 'Account settings | Outgoing server (SMTP)' to 'Normal password'.
Tha coltas nach eil am frithealaiche a-mach (SMTP) %S a’ cur taic ri faclan-faire crioptaichte. Ma tha thu dìreach air an cunntas a shuidheachadh, feuch is cleachd “Facal-faire àbhaisteach” mar an dòigh dearbhaidh ann an “Roghainnean a’ chunntais | Roghainnean an fhrithealaiche a-mach (SMTP)”.