Problem
When trying to add an invoice to a batch, you receive the error message Action cancelled. Invoice #XXXXXXXXX cannot be added to the batch because it has material/equipment without a technician.
Solution
The error message is caused by a material or equipment on the invoice that does not have a technician assigned to it. Once a technician is assigned to the material, the error message should disappear.
Go to the invoice that triggered the error message.
Check each material listed on the invoice.
Assign the appropriate technician to any material that does not have one assigned.
Save the changes.