401 Authorization Required when calling get_bars for a long time

Hi Support and Community,

I have a script that calls

alpaca_api.get_bars(symbol=symbols, timeframe=timeframe, start=YESTERDAY,
                                                   end=TODAY, adjustment="split")

in a while True loop during market hours and then do some processing. The above call executes about once every 15 seconds during market hours, which is when I run my script.

After a while, I’d get

requests.exceptions.HTTPError: 500 Server Error: Internal Server Error for url: https://data.alpaca.markets/v2/stocks/bars?timeframe=5Min&adjustment=split&start=2025-11-20&end=2025-11-21&page_token=QVBMRHxNfDE3NjM2ODQxMDAwMDAwMDAwMDA%3D&symbols=AAL%2CAAPL%2CACHR%2CAGNC%2CAMCR%2CAMD%2CAMZN%2CAPLD%2CAVGO%2CB%2CBAC%2CBBAI%2CBMNR%2CBULL%2CCCL%2CCDE%2CCIFR%2CCLF%2CCLSK%2CCMCSA%2CCMG%2CCNH%2CCORZ%2CCRCL%2CCRWV%2CDIS%2CDKNG%2CEOSE%2CET%2CETHA%2CF%2CFCX%2CGOOG%2CGOOGL%2CGRAB%2CHBAN%2CHIMS%2CHL%2CHOOD%2CHPE%2CIBIT%2CINTC%2CIONQ%2CIREN%2CITUB%2CJD%2CJOBY%2CKDP%2CKEY%2CKHC%2CKO%2CKVUE%2CLAC%2CLUMN%2CLYFT%2CMARA%2CMETA%2CMRVL%2CMSFT%2CMSTR%2CMU%2CNBIS%2CNCLH%2CNFLX%2CNGD%2CNIO%2CNKE%2CNOK%2CNU%2CNVDA%2CNVO%2CNVTS%2CONDS%2COPEN%2CORCL%2COSCR%2COWL%2CPATH%2CPBR%2CPCG%2CPFE%2CPINS%2CPLTR%2CPRMB%2CPYPL%2CQBTS%2CQS%2CQUBT%2CRF%2CRGTI%2CRIOT%2CRIVN%2CRKLB%2CRKT%2CSGBX%2CSMCI%2CSMR%2CSNAP%2CSNDK%2CSOFI%2CSOUN%2CT%2CTSLA%2CTTD%2CUBER%2CVALE%2CVZ%2CWBD%2CWMT%2CWULF%2CXOM%2CXPEV

I’m curious why. And how do I resolve it?

Thank you.