I was installing Sitecore Commerce 9.0 update 3 and after a long successful run, it broke out with an error saying that Solr fails to populate schema.After digging out, I found out that this issue is coming from Sitecore-commerce-solr.json has capitalized argument Name that is further concatenated with other arguments into a URL:
https://localhost:8983/solr/admin/cores?action=Create&Name=platformCustomersScope&Configset=basic_configs&wt=jsonwhere it should be with lower case 'n' instead:
https://localhost:8983/solr/admin/cores?action=Create&name=platformCustomersScope&Configset=basic_configs&wt=json
As I later cleared up from Sitecore, the issue comes from using SIF 2.0 for installing XC 9.0 update 3, which is not supported -we should use SIF 1.2.1 instead. However, changing these configuration json file arguments to lowercase make the trick work.