After PrestaShop generates an order and downloads it, there is a 505 error on the server.
After viewing, it should be an error on the server: Allowed memory size of 134217728 bytes exhausted (tried to allocate 72 bytes)
By default, the memory limit of PHP is 128MB. According to this situation, you may need to modify the php.ini file to increase the size of PHP memory.
Modifying the memory_limit configuration in the configuration file to 256 MB can avoid this problem.