I am seeing errors when attempting to create new project tasks or checkpoints using Jive-n Cloud. The system appears to think it tis either an invalid date format or that the checkpoint is before the project started - when it clearly isn't.
Any ideas? - the function was working until recently.
From your description it's possible you are running into a recently discovered issue in the Jive Cloud platform being tracked as JIVE-65272. To confirm, I would recommend submitting a case in your customer group here in the Jive Community where the next available support engineer can assist in confirming the issue.