Ok the text was enough to see the case. Indeed the server terminated the connection non-properly and this is what gnutls is reporting. This is reported via the GNUTLS_E_PREMATURE_TERMINATION error code (in gnutls 2.x the generic GNUTLS_E_UNEXPECTED_PACKET_LENGTH was used). Maybe you could report this to the evolution developers to report the error only without invalidating the already received data. I know that other libraries just ignore this error, but note that if you ignore it you'll never notice an attack that truncates the data sent by the server. From gnutls side there is not much we can do.

Unfortunately I cannot open this format with wireshark. Could you save it on libpcap format (the first option in save as).

Download and use the "wireshark" program. Use it to capture data from the interface that you use to access your e-mail (ethernet or so). Then save the output and attach here.

Hello the fix might solve the problem you see with evolution but I'm not sure it is the correct fix. It might as well be right to fail because the peer abnormally terminated the connection (in TLS one has to terminate a connection by the protocol and not just terminate the TCP layer). Could you provide a tcpdump of the failed TLS session to verify that this is the case?