Creation of a new german site collection (LCID 1031) from CSOM fails with error "Locale 1031 is not a supported locale" (see attached code). On the same tenant with the same account the creation of an english site collection (LCID 1033) works. Also the creation of a new german site collection (classic team site) from the SharePoint admin UI works. I checked on other tenants - the same code works there and new german site collections can be created using CSOM. I was not able to find any setting on the tenant that would restrict the supported LCIDs. So far I guess there are two possibilities: Either there is a setting to change the supported LCIDs on the tenant (and I haven't found it yet) or there is something wrong with my tenant.
Any help is much appreciated!