Unable to (re)create RFC destinations in solman_setup

[symon_braunbaer]

Dear Experts,

this is VERY weird !!! Just 2 days ago I did the managed system setup for a newly installed S/4 Hana system. 
EVERYTHING went fine! When checking today, the point about RFC destinations was red !!

When I try to reexecute the step, I am getting the following error:

I repeat that I did not have ANY issue like that just 2 days ago! And of course, when I try to login directly with these credentials in this client, I am able to login without any issue.
I still thought that I already know this problem and I turned to an SAP note that was already known to me:

2694331 - Login RFC: Name or password is incorrect error on Maintain RFCs step - Solution Manager 7.2

Nevertheless it does NOT help 😞 I have tried settings 0, 1, and 4. I even tried resetting the user name buffer in SU56, but none of that helped and here is where I run out of ideas 😞 So, I would really appreciate any help and advice! Many thanks!

[symon_braunbaer]

UPDATE: I took a reference system that I connected to the Solution Manager a few days earlier and where the RFC destinations are green. I created test RFCs from the Solution Manager to both systems. In the reference systems, when doing an authorization test, it goes through fine. On the problematic system, it pops up a login dialog. I have compared the auth/system parameters between the problematic and the reference system. Both have these:

I kept trying the SM59 authorization test against the problematic system while changing the parameter auth/rfc_authority_check. It seems that this parameter has no influence on the SM59 authorization test. No matter which value I put (without restarting the system, as it is a dynamic parameter) it kept bringing up the login dialog. Then I have tested the function module RFC_SYSTEM_INFO and that runs with values lower than 4 and fails for higher values, exactly as expected.

And now I truly ran out of ideas and hope you provide me with some fresh tips. Many thanks!

[Vera_Jiang]

Hi Symon,

[Vera_Jiang]

Hi Symon, it looks like a RFC user being locked. Not sure which RFC reports the error? Best regards,

[Vera_Jiang]

The error doesn't talk about the DDIC user. It talks about RFC user, mostly the READ. Did you check READ RFC user? Which RFC did you test and got the login pop up screen?

[symon_braunbaer]

I found the cause: snc/enable = 1. When I set it back to 0, RFCs are working again. But what is the solution ? We do not have this problem on our ERP system and the parameters are the same !!! It must be some new "feature" of S/4 Hana !!!

[Vera_Jiang]

good job symon

[symon_braunbaer · Accepted solution]

Hello Vera,

thanks a lot. No, the user is not locked, that was the very first thing I checked. As I wrote, I can login to the 
system with this user in SAP GUI without any issues.
I am rather wondering why the RFC authorization test is popping up a window. There is probably some other
security parameter that tightens up security way too much 😕

[symon_braunbaer · Accepted solution]

For now I can only confirm, that the problem is caused by a parameter. I reverted back to old parameters and RFC connections are working. However we changed so many parameters at once that it will be VERY difficult to find the culprit.