[galaxy-user] Workflow does not run

Hello! I have a question about a workflow I have created from my history. I can edit and view it, but when I try to run it, a white page appears and I cannot do anything. I have created other worflows which perfectly run, but I don't know why this one doesn't. It includes 4 steps for GATK pre-processing steps (Indel Realigner, Count Covariates and Table Recalibration). What can the problem be? I would appreciate any input! Thanks Debora