I have installed 2 Mercury Servers for testing purposes.

I tried tend a batch of 5 messages, using MercuryE on sender and MercuryS on receiver, and SSL on both (self-signed certificates)

Messages 0 1 2 4 arrived

Message 3 failed with "8: Socket read timeout" appearing in the log

That is the best characterization I got

On the Receiver's side, (MercuryS)

The lo is:

08:36:33.401: << 220 OK, begin SSL/TLS negotiation now.<cr><lf>
08:36:33.591: [] SSL/TLS session established
08:36:33.591: [] TLS_AES_256_GCM_SHA384, TLSv1.3, Kx=any, Au=any, Enc=AESGCM(256), Mac=AEAD<lf>
08:36:33.592: [] No peer certificate presented.
08:37:03.857: 8: Socket read timeout
08:37:03.858: >>
08:37:03.872: [] OpenSSL secure session normally terminated.
08:37:03.873: --- Connection closed at 27 Mar 2023, 8:37:03.873. ---
08:37:03.874:

What should I do