SAP Business One 9.1 license key is not compatible with SAP Business One 9.2. Therefore, please make the version of license key installed is correct.
If you have used version 9.1 license key in version 9.2, the SAP SLD Service will crash when click 'Update' in License Administration - User License assignment.
The error message "MESSAGE 60070 - 99999987" that pops up during license assignment resulting in inabilityof assign the license to new users + SAP B1 Server restart can point to an issue with the B1Upf.xml file or the license file stored locally itself.
In order to try to resolve the issue with the licensing, could you please try out following steps :
1. Close all SAP Business One clients. Make sure that your original license file obtained from the portal is available.
2. Navigate to the folder C:\Program Files (x86)\SAP\SAP Business One ServerTools\LicenseHTTPS\webapps\lib
3. Make a copy of the B1Upf.xml file and save it with a different name or in a different folder.
4. Make a copy of the B1LicenseFile<-installationname>.txt and save it with a different name or in a different folder.
5. Delete the originalB1Upf.xml and B1LicenseFile<-installationname>.txt files from the folder
C:\Program Files (x86)\SAP\SAP Business OneServerTools\LicenseHTTPS\webapps\lib
6. Restart SAP Business One Server Tools Service
7. Navigate to the SLD URL -> Services-> License Manager and import the original license file
8. Connect to SAP Business One client and reassign licenses for all users under Administration → License → License Administration.
In case of any issue would happen after these steps, you can always put the backups of B1Upf.xml and B1LicenseFile-.txt back to the original folder.
Any issue, please attach the recent sldService log file to SAP support in below folder:
C:\ProgramData\SAP\SAP Business One\Log\SAP Business One ServerTools\SystemLandscape Directory