Any attempt to create a new classic ad results in the following error popup with a varying ‘minimum’ based on budget:
Creation Failed
Campaign.LifetimeBudgetMicroUsd cannot be less than the minimum '55000000' for the selected duration
Please try again later. If the problem persists please contact operations for support.
Code: INVALID_ARGUMENT
Page URL: https://advertise.roblox.com/new/campaign
I can confirm this is still occurring 2 days later.
New information on this error: It is related to the campaign start/end date. There seems to be an inconsistency between what the UI shows as an acceptable budget/range and what submitting does. Letting the campaign expire a day earlier is a workaround to avoid this error.