Excel add-on (.vtso) error message while installing

For academic research purposes I try to use the Text2data sementic analytic tool for Excel (the installation zip can be found here)

However, I get an error message and I'm not sure how to fix this. The error message I get is: Customized functionality in this application will not work because the certificate used to sign the deployment manifest for TEXT2DATA FOR EXCEL or its location is not trusted. Contact your administrator for further assistance.

DETAILS

     Name: TEXT2DATA FOR EXCEL
     From: file:///C:/Users/User/Downloads/Text2dataExcelAdd-In                            (1)/Text2dataExcelAdd-In.vsto

     ************** Exception Text **************
     System.Security.SecurityException: Customized functionality in this          application will not work because the certificate used to sign the deployment          manifest for TEXT2DATA FOR EXCEL or its location is not trusted. Contact your administrator for further assistance.
        at          Microsoft.VisualStudio.Tools.Applications.Deployment.ClickOnceAddInTrustEvaluato         r.VerifyTrustPromptKeyInternal(ClickOnceTrustPromptKeyValue          promptKeyValue, DeploymentSignatureInformation signatureInformation, String          productName, TrustStatus status)
        at          Microsoft.VisualStudio.Tools.Applications.Deployment.ClickOnceAddInTrustEvaluato         r.VerifyTrustUsingPromptKey(Uri manifest,          DeploymentSignatureInformation signatureInformation, String productName,          TrustStatus status)
        at          Microsoft.VisualStudio.Tools.Applications.Deployment.ClickOnceAddInTrustEvaluato         r.VerifyTrustUsingPromptKey(Uri manifest,          DeploymentSignatureInformation signatureInformation, String productName)
        at          Microsoft.VisualStudio.Tools.Applications.Deployment.ClickOnceAddInDeploymentMan         ager.ProcessSHA1Manifest(ActivationContext context,          DeploymentSignatureInformation signatureInformation, PermissionSet          permissionsRequested, Uri manifest, ManifestSignatureInformationCollection          signatures, AddInInstallationStatus installState)
        at          Microsoft.VisualStudio.Tools.Applications.Deployment.ClickOnceAddInDeploymentMan         ager.VerifySecurity(ActivationContext context, Uri manifest,          AddInInstallationStatus installState)
        at          Microsoft.VisualStudio.Tools.Applications.Deployment.ClickOnceAddInDeploymentMan         ager.InstallAddIn()
     The Zone of the assembly that failed was:

I've added the map where the .vtso file is in to the Trusted Center Locations in Excel>Options>Trust Centers but this didn't have effect, does someone know how to fix this?