Web url data (table on sharepoint) refresh - credentials error on enterprise gateway

We are kinda speculating here to rescue you through your issue as it is not really clear what the reason might be. However i can suspect a versions non compatibility along the process of refreshing your report. could be the sharepoint, the Gateway or the desktop.

So give it a last try and install a personal Gateway( your machine has to be 64 bits) in your computer and use it. If it works then the entreprise Gateway needs to be updated, else the sharepoint or your desktop.

https://docs.microsoft.com/en-us/power-bi/connect-data/service-admin-troubleshooting-power-bi-personal-gateway

Hope this will save you.