My Cloud (MAC Version) not sending Share Invitation E-mail

Sorry if this topic has been raised in the past, but MY Cloud (MAC Version) does not issue the Share Invitation E-Mail. The Message Banner appears on screen suggesting that such a notification has been despatched and will arrive shortly but nothing happens. According to the ADMIN Panel the firmware is the latest version V04.05.00-342 . Any help would be appreciated.

I have this problem, too… Mac Version… Feb. 2020