"Your plan allows N forms per app"

Every plan limits how many forms (one per Form_ sheet) a single app may define — for example Basic 2, Pro 4, Max 6, Enterprise unlimited. If a workbook has more, creating or changing the app is refused with a message naming your plan and its limit.

Fix it

• Remove a 'Form_' sheet from the workbook so the app fits your plan, or
• Upgrade your plan in Admin console → Plans for more forms per app, then re-upload.

Good to know

• This is a per-app cap, not a workspace total — each app is counted on its own.
• In creation wizard's review step you will be notified, if you exceed the plan limits.