3025047 - SUM: The Installation/Upgrade Package for Add-on SAP_UI rel. 754 is not available

During an update, the Software Update Manager (SUM) stops in phase PREP_EXTENSION/EHP_INCLUSION, with errors below in the log file EHP_INCLUSION.LOG:

1EETQ399 Last error code set is: Unable to generate addon queue. Return Code = 1, Reason =
1EETQ399X"The Installation/Upgrade Package for Add-on SAP_UI rel. 754 is not available", check log file
1EETQ399X'SPDA_EHP_INCLUSION.LOG' for details
1EETQ399XIf you put new packages in the download directory, use option 'init' to upload them
1EETQ204 Upgrade phase "EHP_INCLUSION" aborted with severe errors ("")

The log file SPDA_EHP_INCLUSION.LOG contains this error below:

3 ETN256 You want to install the following add-on components:
3 ETN248    Component: "UIBAS001" rel. "500", Support Package level: "0" (component type "W")
2 ETN085X"Calculate pure CRT Queue" "for installed Add-ons" "and already applied Support Packages" " "
3 ETN112 The OCS Package Queue is empty
2 ETN085X"Adding Add-on Installation Queue" " " " " " "
2WETN260 The Installation/Upgrade Package for Add-on "SAP_UI" rel. "754" is not available

• Software Update Manager (SUM)
• SAP NetWeaver

UIBAS001 500, SAP_UI 754, not available, NetWeaver, SUM, Software Update Manager, PREP_EXTENSION/EHP_INCLUSION, stack.xml file, Maintenance Planner, reset, SUM guide, Unable to generate addon queue, SPDA_EHP_INCLUSION.LOG, option 'init', UIBAS001, Calculate pure CRT Queue , KBA , BC-UPG-TLS-TLA , Upgrade tools for ABAP , Problem