Unable to Authenticate on Web Client for my VCenter server

[bwilsey84]

All of a sudden I am receiving an unable to authenticate when trying to use the VSphere Web Client when logging into a VCenter server running VCenter server 6. I can however authenticate and log in with the same credentials when I use the normal VSphere Client but I need to access feature that are only available in the web client. The VCSA is a virtual machine on an ESXi host running ESXi 5.5. Im pretty new to VMware and Im not sure where to even start troubleshooting. Any help is greatly appreciated

[Gidrakos]

Can you get in as a local administrator? (administrator@vsphere.local)

It almost sounds like the host reverted to having local logins be default, rather than your domain. The "thick" client will push your domain credentials explicitly, while the Web Client (by default) will not - that's why I'm curious if the domain has been removed from default.

Go to Administration --> Single Sign On --> Configuration --> Identity Sources to view/change what the default is