Anyone else having issues with Post Office Saver 6-digit security code

itm2

I opened a Post Office savings account in April. SInce then I've logged into it maybe 3-4 times. Each time I am prompted to enter 3 digits from my 6 digit security code. At least twice now, it has rejected the details that I have entered, despite me taking extreme care when entering them. In today's case, I successfully entered the code to login, but when trying to withdraw funds it asked to enter numbers from the same code again, but it rejected my entries 3 times. I was super-careful on the 2nd and third attempts because of the problems that I'd had in the past. I am now locked out of my account again, and need to wait 3-5 working days to receive a new code in the post. This is the 3rd time that this has happened since April.

Has anyone else had problems with their 6 digit code on a PO savings account? I know it would be unthinkable that a Post Office computer system could have any kind of defect, but I thought I'd ask....