Hi @Luis Rodriguez
Yes, Event 1008 with the same source will be logged for any errors that are encountered, such as when the EM service cannot reach the OCS(Office Config Service).
Ensure that your Exchange servers can communicate with the Internet to validate the certificate chain.
simulate the behaviour of the EEMS by getting the test page with a browser (https://officeclient.microsoft.com/getexchangemitigations). For those of you not being familiar - look at the schema links in the XML document as well as the certificate of the URL and check all the certificate chaining, revocation lists URLs and so on.
For the IPs compare the blocked IPs with the following networks and allow them:
https://www.microsoft.com/en-us/download/details.aspx?id=53602
https://www.gstatic.com/ipranges/goog.json
https://github.com/SecOps-Institute/Akamai-ASN-and-IPs-List/blob/master/akamai_ip_cidr_blocks.lst
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