Message: “System Error.” “Cant get emails.”

I am currenty using two laptops, both using Windows 10.  I am still using Windows Live Mail, which I find is far more flexible than Yahoo or Gmail.  Three email accounts:  Sky, BTinternet and Outlook.com.  Access Sky and BTinternet through WLM and Outlook.com through the Windows 10 app.  All three accounts are displaying the message as shown in the subject heading above, when I check their status on the Outlook.com page. 

All of my Sky emails were deleted at the beginning of May, and then again, today, May 22, 2019.    

ISP is Sky, who will tak no responsibility and do not know what to do, anyway.  I have tried all the recommended remedies, including deleting WLM and then reloading.  It downloaded over 1000 messages on the BT and Sky accounts.  

Also tried Start/Settings/Privacy/email/Allow App to access emails/ - no result.

Sky intermittenty permit access, but then the icons will disappear from the desktop, and come back again.  The situation has worsened since I advised them that I was porting out of their comany to another.  So, some of this may be their way of retailating for loss of business.

I think that Sky switched to another transmitter at the beginning of May, but that is only a guess.  Something is certainly NOT going on,

Any suggestions, please.  Please bear in mind that I am nearly 80 years of age, and although I probably know more than my age group, I am "flummoxed!"