Famous operational issues

Tue Feb 16 21:28:35 UTC 2021

Since you said operational issues, instead of just outage...

How about MCI Worldcom's 10-day operational disaster in 1999.

http://www.cnn.com/TECH/computing/9908/23/network.nono.idg/
How not to handle a network outage

[...]
MCI WorldCom issued an alert to its sales force, which was given the 
option to deliver a notice to customers by e-mail, hand delivery or 
telephone – or not at all. After a deafening silence from company 
executives on the 10-day network outage, MCI WorldCom CEO Bernie Ebbers 
finally took the podium to discuss the situation. How did he explain the 
failure, and reassure customers that the network would not suffer such a 
failure in the future? He didn't. Instead, he blamed Lucent.
[...]