Weak TLS cipher negotiated
The server selected a cipher whose name contains RC4, DES, NULL, EXPORT, ANON, or MD5.
Why it matters
Those ciphers do not provide modern confidentiality or integrity.
What to do
Disable them and prefer AEAD suites such as AES-GCM or ChaCha20-Poly1305.
Reference
Certificate validity, protocol version, and cipher choice determine TLS trust and strength.