I have not used this site for many years; but would think this is still accurate. If anyone knows a better site; please let us know. Bounced email is a rare event these days.
My best guess is too much data. Schools closed, with students online from home. Families/adults at home midday and streaming to the max with Netflix, Hulu, Disney or whichever; text/email traffic for those checking on one another, etc.
I've received 6 bounced email notifies, from mail sent early Monday morning........for our location, Comcast.net and Charter.net. Internet Traffic Report