If you receive the mentioned Add-in error in Excel 2016. Please follow the steps given below to resolve the issue .

Step 1:  In Internet Explorer, click the Tools button, and then click Internet Options.

Step 2: Click the Security tab, and then select the Internet Sites Zone.

Step 3: Select the Enable Protected Mode check box, and then click OK.

Step 4: Restart Internet Explorer and Excel and try again.

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