I am using Apple devices (iPhone & iPads).  I use Microsoft outlook to handle my Mail on these devices.  I am using Application specific passwords on these devices to access my zohomail account on outlook.

The “annoyance” is that I am required to re-sign in very often.  The frequency varies but it has happened on my iPhone three times in the last three days. After signing in, then everything works fine … for a day or two.  And then I have to repeat the sign in process again.  

This only happens on one device at a time …. Meaning that if I am required to sign in on one of my three iOS devices (iPhone or two iPads) … the other two devices do not require a new sign in.

This never happens with my gmail or hotmail accounts that outlook is also managing.  It happens only with zohomail.