2580295 - SUM: PREP_PRE_CHECK/PROFREAD fails when SNC is enable

Running an upgrade with SUM tool, in a system where SNC is configured, the PROFREAD phase stops with the following error:

1 ETQ200 Executing actual phase 'PREP_PRE_CHECK/PROFREAD'.
1 ETQ399 Phase arguments:
2 ETQ399 Arg[0] = ''
4 ETQ399 Starting dialog 'Passwords' at  .
1 ETQ359 RFC Login to: System="<SID> ", AsHost="<hostname> " Nr="xx", Client="xxx", GwHost="<hostname>", GwService="sapgwxx"
2EETQ231 RFC Login failed
4EETQ399 Dialogue validator 'DDICValidator' failed with 'DDIC password does not work:
4EETQ399 RFC login to system <SID> ashost <hostname> nr xx gwhost <hostname> gwservice sapgwxx failed with code 2 key RFC_LOGON_FAILURE: Unencrypted communication is rejected by this system.

Netweaver system with SNC configured

PROFREAD, RFC_LOGON_FAILURE, Unencrypted, SNC , KBA , BC-UPG-TLS-TLA , Upgrade tools for ABAP , Problem