The issue of our backend serving bad codecs should be resolved. This is the SHA1 error you might have seen in your logs.
What could also have happened is whenever you attempt playback and codec is missing, PMS would attempt to download them again. However It fails (SHA1) again, again, and again. This then flags the IP address (where ever the PMS is installed) as requesting too many times (429).
So if you were flagged by 429 and continue to attempt playback you would continue to receive the 429 errors and not download the update codecs. If you never waited to reset whatever limit is set that triggers the 429 response, then you would continue to see this issue.
I’m not 100% sure that 
is 100% accurate with regards to timeout but the gist of the situation is right. If you are seeing 429 errors when attempting to download codec, you need to wait a bit then try again.
It depends on what you’re seeing in your logs.
