The following commands can possibly help in investiagting various problems related to accounts on Sailfish OS.
1) List existing accounts and their account IDs
The account IDs are the numerals 1,2,3,...
2) List all settings of an account (ID)
ag-tool list-settings <accountID>
3) Change authentication method
ag-tool update-service <account-ID> email int:imap4/authentication=1
The command above is an axample to change that authentication method setting to "1" which is "Login".
4) Delete an account (ID)
ag-tool delete-account <accountID>
5) Delete all accounts
ag-tool delete-account all