Because Office 2013 no longer receives security updates, it is highly recommended to switch to a supported version:
Since Microsoft Office 2013 Professional Plus reached its end of support on April 11, 2023, Microsoft no longer provides official downloads or activation assistance for it. Using unofficial "activators" can pose significant security risks, including malware and data theft. microsoft-office-2013-professional-plus-with-activator
Unlicensed Product and activation errors in Office - Microsoft Support Because Office 2013 no longer receives security updates,
: If internet activation fails, you may still find a "Phone Activation" option in the Activation Wizard, though this is increasingly unsupported for older versions. microsoft-office-2013-professional-plus-with-activator
: One-time purchase versions that are officially supported on Windows 10 and 11 .