unicorn deployment failure - can't sync when deployed to real environments

I am sure I am missing something simple about using Unicorn in environments above the local dev environments

the source folder is correct out of Azure Paas, out on my App Service

I am in Sitecore 9.3.0

and Unicorn 4.1.1

The source folder is set to the real folder the src was deployed to…

<sc.variable name="sourceFolder" value="D:homesitewwwrootApp_DataSerializationsrc" patch:source="Foundation.Serialization.config"/>

But the unicorn control panel claims I need to do an initial serialization, that it cannot sync

Warning: at least one configuration has not serialized any items yet. Unicorn cannot operate properly until this is complete. Please review the configuration below and then perform initial serialization if it is accurate.

Is there some other setting, some other config I need to make to tell Unicorn is should use the serialized yml files from the sourceFolder location or…

Not sure what I am doing wrong here