2264788 - SAP Web Dispatcher : WARNING => Failed to read group info for system <nr>

In the SAP Webdispatcher trace file the following messages appear:

[Thr <nr>] *** WARNING => Failed to read group info for system <sid> (ABAP,HTTP): Internal ICM error(-1) [icrxx.c 6785]
[Thr <nr>] *** WARNING => Failed to read URL prefix info for system <sid> (ABAP,HTTP): Internal ICM error(-1) [icrxx.c 6785]

or

[Thr <nr>] *** WARNING => Failed to read group info for system <sid> (ABAP,HTTP): Redirect response received(-64) [icrxx.c      3745]
[Thr <nr>] *** WARNING => Failed to read URL prefix info for system <sid> (ABAP,HTTP): Redirect response received(-64) [icrxx.c      3745]

or

[Thr <nr>] *** ERROR => Connection request from (-1/0/255) to host: [backend hostname], service: [backend port] failed (NIECONN_REFUSED) {000b5037} [icxxconn.c 3380]
[Thr <nr>] *** WARNING => Failed to read group info for system [SID] (ABAP,HTTP): Network error (NI)(-8) [icrxx.c      3795]

or

[Thr <nr>] *** WARNING => Failed to read group info for system <sid> (ABAP,HTTP): Found(302) [icrxx.c 3668]
[Thr <nr>] *** WARNING => Failed to read URL prefix info for system <sid> (ABAP,HTTP): Found(302) [icrxx.c 3668]

SAP Web Dispatcher all versions

checkconfig, internal ICM error, Found(302), SSL_ENCRYPT, CONFIG_PROTOCOL, Internal ICM error(-1), Failed to read group info, Failed to read URL prefix, Redirect response received(-64), /sap/public/icf_info/icr_urlprefix, /sap/public/icf_info/icr_groups, wdisp/ping_protocol, wdisp/group_info_protocol, wdisp/url_map_protocol, wdisp/server_info_protocol , KBA , BC-CST-WDP , Web Dispatcher , BC-CST-IC , Internet Communication Manager , Problem