I have a Mate 20 Lite and I use the stock app to view and send mails. I have connected it with all my accounts, gmail, yahoo, hotmail and sch (national school network). With the first 3 providers I have no problem. With the last one, I can see attachments normally in most mails but not all of them, as you can se in the pictures attached below. If I visit provider's web page, via computer or my phone, I can see attachments with no problem. Is there something wrong with the mail app? I had the problem with android 8.1 and I still have it with android 9 and EMUI 9.1.0.215.