My experience over the past month or more is that Hotmail/Outlook.com was being slowed significantly by the app, to the point that it is causing errors (sent an email last night, there is no record of it being sent). For some time now I get continuous msgs when trying to open folders in Hotmail where it would take some time to try and open & then indicate either nothing in folder or to try again, or possibly finally open. At times my emails cannot be sent & a msg is relayed that cannot send currently & to try again another time. Very frustrating.
I had previously been using app for some time (& previous version?) without any major issues. I know it is this app because I had no problems operating Hotmail in google chrome. I also disabled this app & then used another one in firefox & no problems opening any folders. So fault is with the app (updated August 2019 I believe), which may have been the time when these issues started.
I hope Adblock Plus can resolve this.