connection interrupted on the ASDM interface.

Good morning everybody,

After successfully configuring NAT on a cisco ASA5510, I have a problem
with the ASDM access.

I have created an ssl certificate request, and successfully imported the  
X509 certificate in the Cisco.

I also had set up a subdomain that points to the external IP address of
the Cisco, for instance admin.red2.co.uk.

For privacy reasons, I have changed the subdomain name, which is not
admin.

Yesterday, I have successfully acceded the asdm, using http server
enable, and adding my IP address.

But now, whe I try to access to the cisco asdm using https secure
connection, and port 443, I have the error :
"admin.red2.co.uk interrupted the connection."

I had try to debug the connection using the command "debug http 255", but
the only message I receive from the console is :
-----
red2asa1(config)# listen: Received HTTP request.
Started http listen on interface ext port 443
-----
Nothing more.

Some other informations may be useful :
===========================================================
red2asa1(config)# show crypto ca certificates
CA Certificate
  Status: Available
  Certificate Serial Number: 04e4da
  Certificate Usage: General Purpose
  Public Key Type: RSA (1024 bits)
  Issuer Name:
    ea=support@cacert.org
    cn=CA Cert Signing Authority
    ou=http://www.cacert.org
    o=Root CA
  Subject Name:
    cn=admin.red2.co.uk
  PrincipalName: admin.red2.co.uk
  OCSP AIA:
    URL: http://ocsp.cacert.org /
  Validity Date:
    start date: 15:57:55 GMT Mar 29 2008
    end   date: 15:57:55 GMT Sep 25 2008
  Associated Trustpoints: cacert
===========================================================
red2asa1(config)# show crypto ca trustpoints

Trustpoint cacert:
    Subject Name:
    cn=admin.red2.co.uk
          Serial Number: 04e4da
    Certificate configured.
===========================================================
red2asa1(config)# show running-config asdm
asdm image disk0:/asdm-523.bin
asdm history enable
===========================================================

Any idea ?