Check the File Repository Usage and to Remove “Unnecessary Files”
In the Saas Edition, the maximum save capacity for "Attachment" has been set depending on the license. For example, the maximum capacity of 100GB (and up to 100 people registration) has been set on "SaaS 100 license". Files that "Attached to Workflow" and "Attached to Task Feed" will be aggregated as capacity. Capacity limit is reached, a new process will not be able to start. If you continue to use within the license, please delete unnecessary files.