no valid recipients resolved error

i have a send email node to send emails for the tagged users(more than 1 user),but its showing no valid recipients resolved error...please help to resolve this error..

iam using the attached expression rule to get email address of tagged users which is stored as username in database table and the value from the rule is saved to a process variable called toaddress.

joinarray(   reject(     a!isNullOrEmpty,     a!forEach(       items: trim(split(pv!feed['recordType!{72d90253-0fad-4ef3-a658-3550c2118c0f}CMS Feed.fields.{4d9a4253-b58a-4749-9552-f533ef1926ba}tagUsers'], ";")),       expression: user(fv!item, "email")     )   ),   ";" )