[Bug]: Invalid Character in Auto-Generated Domain Names Causes SSL Certificate Failure

[JuanPabloAmador]

Description

I have encountered an issue when deploying new services in Coolify where the automatically generated subdomains contain invalid characters. Specifically, the subdomains often include underscores (_), which are not valid according to DNS standards. This results in SSL certificate generation failures when using Let's Encrypt.

Please let me know if you need further details or logs. Thank you for your help!

Minimal Reproduction (if possible, example repository)

1º Set up Coolify with a wildcard DNS record pointing to a Hetzner VPS (e.g., *.coolify.mydomain.com).
2º Deploy a new service in Coolify, which automatically generates a subdomain name.
3º Observe that the generated subdomain includes an underscore (e.g., codeserver_8443-i0g48ckkg8cwgw804sg0w0og.coolify.mydomain.com).
4º Coolify attempts to generate an SSL certificate via Let's Encrypt, which fails due to the invalid character in the subdomain.

Expected Behavior: Subdomains should be generated using only valid characters (letters, numbers, and hyphens), adhering to DNS standards.

Actual Behavior: Subdomains with underscores are generated, causing the following error from Let's Encrypt

Exception or Error

Domain name contains an invalid character
unable to generate a certificate for the domains [codeserver_8443-i0g48ckkg8cwgw804sg0w0og.cool.mydomain.com]: acme: error: 400 ...

Version

v4.0.0-beta.335

Cloud?

• Yes
• No