Subdomain with _ not working

Describe what you would like to know or do
I tried to open a wss connection to a host with a _ in the subdomain, but it says 'java.security.cert.CertificateException: Illegal given domain name'

Describe the solution you'd considered
Can I change 'IDN.USE_STD3_ASCII_RULES' to '0' or something else?

[marci4]

Most likely an outdated runtime, see https://stackoverflow.com/a/48444910

Most likely an outdated runtime, see https://stackoverflow.com/a/48444910

I tried to update to java 16 and java 11, nothing changed.

[marci4]

Not much we can do here. We have no control over the exception cause.

I found an API that fixed it, thank you for your help.

[marci4]

You mind sharing with others having a similar issue?

oh, I dont know the project, I am on my mobile rn