Error: SEC_ERROR_UNKNOWN_ISSUER

[SergeantBlyat]

Describe the bug
When clicking on a shortened link, web browser sometimes shows a warning that the website is a potential security issue.

To Reproduce
Steps to reproduce the behavior:

1. Go to any ishortn shortened link
2. See error
3. Click Advanced to see the error code

Expected behavior
Should redirects to the original link, but shows the warning page instead.

Screenshots

Desktop (please complete the following information):

• OS: Windows 11, MacOS
• Browser: Chrome, Firefox, Safari, Edge
• Version: N/A

Smartphone (please complete the following information):

• Device: iPhone 15, Realme 7
• OS: iOS and Android
• Browser: Chrome, Safari
• Version: N/A

Additional context
This happens from time-to-time, and only for a few hours, but it affects some users quite a bit. I've confirmed this issue happens both when open the shortened link while using coporate network either on-premise and over VPN, and private network such as home network or mobile data.
The domain ishortn.ink seems to also be blacklisted on SUBL. So that's that.