Hi @Salah - I don’t think there can be a general problem with version of the installer else loads of people would be shouting about it. I used that version to try Noble and then go back again earlier in the week on my 3a and it worked fine. The only time I’ve had anything like that was when I had a dodgy USB connection. Which installer did you use to install UT previously?
Don’t know if some server being down would cause the same, but would have thought more people would be complaining if so. Good luck and hope someone more knowledgeable can suggest something.