My CEO has the exactly same issue since beginning March 2017.
I tried everything, from checking all the Settings if whatsapp is allowed to store pictures automatically until reset the complete phone and at least replacing the iPhone 6+ with an brand new iPhone 7+.
But also that... no luck, he still gets the same error message.
Interesting was, that before I ordered a new iPhone, I configured the WhatsApp on an iPhone 6s.
And there it worked. And after I verified the iPhone 6+ again, the issue went back BUT some pictures started to show up in the Camera Roll. WHY??
Also I downloaded all pictures from the iphone via computer (iphone connected as a drive) and synchronized them back on the iPhone via iTunes. And my CEO told me some hours later, that some pictures are there which he couldn't save from WhatsApp. So that means they were on the mobile, but were not showing in the camera roll...
My questions in this case:
- does WhatsApp have user based settings connected to the account?
- are some settings for WhatsApp connected to the Apple ID or iCloud?
- Does the iPhone have an issue to "search/index" the WhatsApp Media folder because of something and that something gets backuped to the iCloud with the WhatsApp Backup?
I already sent multiple emails to the WhatsApp support... automated answer as usual...
- wait for the next update
- read the FAQ
Cheers