This has to do with the periodal wage tax return that JAM! does at the Belastingdienst (tax authorities). If your WW request has been submitted right before this wage tax return, then the Belastingdienst misses the required information. As a solution, you can download your payslips yourself via your documents in MyJAM! and share these with the UWV. That is sufficient to complete your WW request. If this is not sufficient, please contact us via