Hello, rutendo32. Thank you for posting to the Apple Support Communities. We understand your situation and how you have noticed a problem when making FaceTime calls using your iPad. We want to be sure that you can stay connected with FaceTime, and we’re happy to help you with this.
It sounds like you have completed some great troubleshooting on your own already and we’re happy to continue from here together. To get started, we’d like to provide you with instructions from the following Apple Support article. This article explains which steps to try first if you are noticing a problem when making FaceTime calls:
If you can't make a FaceTime call on your iPhone, iPad, or iPod touch - Apple Support
According to the article above, in addition to what you have tried so far, you should also check the date and time settings on your iPad. Please open Settings > General > Date & Time and turn on Set Automatically here.
You can also open Settings > FaceTime and toggle FaceTime off, and then back on here.
Finally, please be sure that you are using a fast connection when making FaceTime calls. FaceTime requires a broadband connection. You can read over the recommended Wi-Fi settings for Apple devices in this last article:
Recommended settings for Wi-Fi routers and access points - Apple Support
We hope that the information in our reply here helps you get back to enjoying FaceTime again. Please let us know if we can help with anything else.
Cheers!