I have a SSIS project that runs fine in debugging mode.
However, when running it on the server it gives me the error above.

Package is fairly simple, a dataflow from one table to another.
Project connection that has been parametrised.
Changing the connectionstring in the projectparameters from DEV to TEST insures that the dataflow is executing on TEST instead of DEV so when running in debug it is using the connectionstring from the parameter.
It was deployed as is, no environment, no configurations, just running on defaults.

But when deployed it nags me with the error-message above.

Where to start?