SocketException Connection reset

For some reason connecting takes a lot of time (20-40 minutes) and right after that it fails with the exception SocketException Connection reset.
Could someone advice on how to investigate/debug this issue?

lein repl :connect https://<host>/repl
Connecting to nREPL at https://<host>/repl
SocketException Connection reset
        java.net.SocketInputStream.read (SocketInputStream.java:186)
        java.net.SocketInputStream.read (SocketInputStream.java:140)
        sun.security.ssl.SSLSocketInputRecord.read (SSLSocketInputRecord.java:448)
        sun.security.ssl.SSLSocketInputRecord.decode (SSLSocketInputRecord.java:165)
        sun.security.ssl.SSLTransport.decode (SSLTransport.java:108)
        sun.security.ssl.SSLSocketImpl.decode (SSLSocketImpl.java:1152)
        sun.security.ssl.SSLSocketImpl.readHandshakeRecord (SSLSocketImpl.java:1063)
        sun.security.ssl.SSLSocketImpl.startHandshake (SSLSocketImpl.java:402)
        org.apache.http.conn.ssl.SSLConnectionSocketFactory.createLayeredSocket (SSLConnectionSocketFactory.java:436)
        org.apache.http.conn.ssl.SSLConnectionSocketFactory.connectSocket (SSLConnectionSocketFactory.java:384)
        org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect (DefaultHttpClientConnectionOperator.java:142)
        org.apache.http.impl.conn.BasicHttpClientConnectionManager.connect (BasicHttpClientConnectionManager.java:313)
Bye for now!

If I curl the endpoint, it responds instantly

curl -X GET "https://<host>/repl" -H  "x-token: some_token_here"
[

]%       

Start by reproducing the failure with lein repl :connect https://<host>/repl and compare it with the successful curl request, including the token header. Use the provided Java SSL handshake stack trace to trace the HTTPS connection path; done requires identifying the cause of the reset, but the issue provides no proposed fix or project file/test to target.