Problem:  Invoice does not calculate the sales tax or does not recognize the "Active" Sales Tax Agency

Error: (1) "See the math" fails to open side panel

Error: (2) "See the math" opens side panel but displays a message. 

Location and addresses: You are not set up to collect sales tax for this sale. Based on the address you are shipping from and shipping to, you might need to collect sales tax for these agencies. Edit Addresses

"Do you collect sales tax for this agency?"

If you click yes, the following message is displayed: "Another tax agency is already using this name. Please use a different name. (code: "INDIRECT TAX-11202")"

Solution:  (Step 1) Edit the invoice and change the select tax rate drop down box to anything but "Based on location". Click Save.(Step 2) Edit the invoice and change the tax rate drop down box to "Based on location". Click Save. (Step 3) Click on "See the math" it should now display the side panel and the existing tax agency tax breakdown.