When I try to upload the workspace to FME server I get a error message saying "@Value(connection) is either missing or unsupported by this version of FME Server."

In a FME workspace I have a SQLExecutor-transformer, which uses different database connections. I use one PostGIS-database per year called db2020, db2021, db2022, db2023.

When the user needs data e.g. for 2021 a sting is generated, which contains the name of the database, in this case "db2021". This string is called "connection" and is referenced with @Value(connection) in the connection field of the SQLExecutor-transformer. This works locally in FME desktop.

Alle connections are present both on FME desktop and on FME server.

When I try to upload the workspace to FME server I get a error message saying 

"@Value(connection) is either missing or unsupported by this version of FME Server."

Any suggestions or workarounds would be appreciated.