Where did you add columns, in the middle of existing columns, or at the end? The code depends on expecting certain data to be in certain columns, and if you inserted columns in the middle, the data is no longer in the columns where expected.
The code builds the email address by taking the name from column B and the email address from column BO to create a string
Firstname Lastname <[email protected]>
If that data is no longer in the same columns, you will get an illegal email address. I'll bet you copied the error message wrong and it is probably "Outlook does not recognize one or more names."
If the columns changed you need to update this part of the code:
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