After updating to iOS/iPad OS 16, you may see repeated messages in VNC Viewer for iOS asking to allow pasting from another app, as shown in the screenshot below.
To prevent this message from appearing, you need to change a setting added in iOS/iPad OS 16, called Paste from Other Apps.
To change it, open the Settings app on your device and scroll down to find VNC Viewer. Tap on VNC Viewer and you will see the options below.
Tap on the Paste from Other Apps setting, and choose the either the most appropriate option for you:
Ask: The app must continue to request permission to paste content from other apps.
Deny: The app cannot paste content from other apps.
Allow: The app can paste content from other apps without asking for permission again.