Unable to initialize provider plugin on OpenTofu due to invalid signing key

[msproul-onezero]

Description of the issue

We are unable to initialize delineaxpm/tss v2.0.9 on OpenTofu v1.8.6 due to an invalid signing key.

Expected behavior

Running tofu init should successfully initialize delineaxpm/tss provider plugin.

Actual behavior

Initializing provider plugins...
- Finding delineaxpm/tss versions matching "2.0.9"...
- Installing delineaxpm/tss v2.0.9...
╷
│ Error: Failed to install provider
│ 
│ Error while installing delineaxpm/tss v2.0.9: the provider is not signed with a valid signing key; please contact the provider author (authentication signature from unknown
│ issuer)
╵

Your environment

OpenTofu v1.8.6 on linux_amd64
delineaxpm/tss v2.0.9

Steps to reproduce

Create main.tf with the following code block:

terraform {
  required_providers {
    tss = {
      source = "DelineaXPM/tss"
      version = "2.0.9"
    }
  }
}

Run tofu init