Exhange 2003, SBS 2003 - LDAP / Domain Controller issues

Running SBS 2003 SP2 with Exchange Server 2003

Everything is configured / running on the same box -  Exchange server name is ourserver1
                                                                                       DNS server name is ourserver1
                                                                                       Config Domain Controller is ourserver1
                                                                                        Domain Controller is ourserver1
                                                                                        Global Catalog Server is ourserver1........

Been tackling this for nearly two weeks now - lots of LDAP errors in application log - and we keep losing e-mail (cannot send or receive we are not physically losing the messages).

Have tried various solutions including"-

rebooting (always a favourite and it helps for a while)

confirming NTDS settings for server under AD sites and services has Global Catalog box checked (it does)

removing automatically detedted Domain controllers and re-adding them manually (ESM)

removing  manually added domain controllers and going back to automatically detected (ESM)

I've run ldp.exe and can connect to ports 389 (my domain controller and config domain controller ports) and 3268 (global catalog server).

Samples of current errors in application log are as follows:-

Source:  MSExchangeDSAccess      Eventid:2110     Category: LDAP
Process EMSMTA.EXE (PID=4748). Could not bind to DS server ourserver1.Ourdomain.com, error 55 at port 389.

Source:  MSExchangeDSAccess      Eventid:2110     Category: LDAP
Process EMSMTA.EXE (PID=4748). Could not bind to DS server 127.0.0.1, error 55 at port 389.

Source:  MSExchangeDSAccess      Eventid:2115     Category: LDAP   (Warning)
Process EMSMTA.EXE (PID=4748). DSAccess needs to close a connection to the Domain Controller ourserver1.Ourdomain.com due to error 0x80040955.

Source:  MSExchangeDSAccess      Eventid:2102     Category: Topology
Process INETINFO.EXE (PID=5824). All Domain Controller Servers in use are not responding:
ourserver1.Ourdomain.com

I've also attached a copy of the latest dcdiag.exe report I have.

I don't know what to try next....  any help would be appreciated





dcdiaglogjuly18