The Arianne 5 crash was caused by re-using a module from the Arianne 4 in the new rocket without testing. Management declared the module to be "proven" but it was only designed and proven within the flight envelope of the Arianne 4.

The C people tried to blame the crash on Ada's use of exceptions. At the time, exceptions were controversial. The actual crash came after an exception was fired and the C folks insisted that C would have just ignored the error state and carried on. Except that the exception was actually the software manifestation of a hardware signal that would have crashed a C program as well.

Ada had a lot of haters, mainly because it was imposed top-down in a lot of organizations. But also because there was a lot of money behind C and other technologies. C++ was vaporware at the time and was able to promise to be a better version of everything Ada was (just you wait!).

Personally Ada was the coolest language I've ever learned and I still love playing with it.