Runtime error 462 when sending multiple email notifications - excel

Question

I have a worksheet set up to send email notifications when certain cells contain values, such as "75%" and "Due".
Around half the time I get
Runtime error 462
It seems this is because I have not specified elements of my code properly.
Private Sub Worksheet_Change(ByVal Target As Range)
Call Check_Project_Progress
End Sub
Private Sub Send_Email(Optional ByVal email_title As String = "")
Dim olNS As Namespace
Dim olMail As MailItem
Set olNS = GetNamespace("MAPI")
Set olMail = CreateItem(olMailItem)
With olMail
.Subject = email_title
.To = "LearnDataAnalysis#outlook.com"
.Body = "Value reads 75%"
.SendUsingAccount = olNS.Accounts.Item(1)
.Display
'.Send
End With
Set olMail = Nothing
Set olNS = Nothing
End Sub
Private Sub Send_Email2(Optional ByVal email_title As String = "")
Dim olNS As Namespace
Dim olMail As MailItem
Set olNS = GetNamespace("MAPI")
Set olMail = CreateItem(olMailItem)
With olMail
.Subject = email_title
.To = "LearnDataAnalysis#outlook.com"
.Body = "PLA determination due"
.SendUsingAccount = olNS.Accounts.Item(1)
.Display
'.Send
End With
Set olMail = Nothing
Set olNS = Nothing
End Sub
Private Sub Check_Project_Progress()
Dim LastRow As Long, RowNumber As Long
Dim ws As Worksheet
Set ws = ActiveSheet
With ws
LastRow = 500
If 4 > LastRow Then Exit Sub
For RowNumber = 4 To LastRow
If .Cells(RowNumber, "AB").Value = 0.75 And .Cells(RowNumber, "AD").Value <> "S" Then
.Cells(RowNumber, "AD").Value = "S"
.Cells(RowNumber, "AE") = "Email sent on:" & Now()
Call Send_Email(.Cells(RowNumber, "C").Value & " is approaching deadline")
End If
If 4 > LastRow Then Exit Sub
If .Cells(RowNumber, "AC").Value = "Due" And .Cells(RowNumber, "AD").Value <> "S,S" Then
.Cells(RowNumber, "AD").Value = "S,S"
.Cells(RowNumber, "AF") = "Email sent on:" & Now()
Call Send_Email2(.Cells(RowNumber, "C").Value & " has met deadline")
End If
Next RowNumber
End With
Set ws = Nothing
End Sub
Again, the error message is Runtime error 462. I have little idea what I'm doing.

Answer 1

You are getting that error becuase the code is not able to connect to the outlook application.
Try this. I have shown you for Send_Email. Adapt it for Send_Email2 as well.
Private Sub Send_Email(Optional ByVal email_title As String = "")
Dim olNS As Object
Dim olMail As Object
Dim OutlookApp As Object
'~~> Establish an Outlook application object
On Error Resume Next
Set OutlookApp = GetObject(, "Outlook.Application")
If Err.Number <> 0 Then
Set OutlookApp = CreateObject("Outlook.Application")
End If
Err.Clear
On Error GoTo 0
'~~> Check if we managed to connect to Outlook
If OutlookApp Is Nothing Then
MsgBox "unable to connect to outlook"
Exit Sub
End If
Set olNS = OutlookApp.GetNamespace("MAPI")
Set olMail = OutlookApp.CreateItem(0)
With olMail
.Subject = email_title
.To = "LearnDataAnalysis#outlook.com"
.Body = "Value reads 75%"
.SendUsingAccount = olNS.Accounts.Item(1)
.Display
'.Send
End With
End Sub