Issue:
When Vault Professional 2022 is updated to Vault Professional 2023, a separate installation is needed on the Vault Server to install the 2023 Thin Client.
Otherwise, the Vault Thin Client will still try to connect to Vault Pro 2022, like this.
Causes:
The Thin Client installer needs to be run on the Vault Server host, under the 'Install Tools & Utilities' option.