I download data in loops. The performance is not an issue (I have also a short break between the individual series).
The problem is: the download interrupts at different series ( at 3rd, at 10th, at 13th etc) , such that the problem is not reproducible. It seems a matter of performance of the data delivery systems.
My solution now: run the code 10 times, until it works. If not - wait some hours and repeat.... If not: try it on Saturdays, when the systems are less busy (except last Saturday, where it didn't work until... Sunday afternoon...)
It is time consuming and expensive.
Can you help somehow, upgrade your system, give us a hint hot to proceed...
May be a possibility to switch the data center - in my case it is always EMEA1, also when I connect through vpn with an USA - ip.