@Ziv Rivkis Thanks for reaching out and sincere apologies for time taken to respond to this. We are working towards improving our response time significantly.
This is a generic issue which occurs mostly because multiple Exchange servers send many large LDAP queries at the same time, triggering a complete topology discovery for each query.
You need to follow certain steps in order to fix it :
Install this 2961522 Update Rollup 7 for Exchange Server 2010 Service Pack 3
Note :This update can randomize the deferral time for Exchange to send out the LDAP queries of complete topology discovery.
There are few workaround as well, which can be found at : https://support.microsoft.com/en-us/topic/domain-controller-is-overloaded-after-you-change-active-directory-configurations-in-exchange-server-2010-cda9ca1a-5752-423e-5ccf-c72e5f9208ef
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