Issue period: 30 May 2020 10:48:38 to 4th June 2020 14:30:00 UTC.
We had found out that a One of Root SSL certificate expiry on our US server. This has impacted the connectivity for incoming and Outgoing APIs from the clients which have the legacy and old systems.We didn't observe any impact on connectivity with salesforce & Zoho.
Incoming message loss due to provider connectivity for the incoming API Direct Send Message API users, might have face connectivity issues with the API.
Please note, the impact is only seen for users and providers which are on legacy and old systems. Message Delivery for salesforce and Portal Users was not impacted during the period
Resolution: We have updated the SSL certificate for the server and the issue is resolved now.