so many issues with Schwab this year - as long as you've set the browser permissions which has been a general issue on the Turbotax side - there was a comment here that Schwab is still having issues their side so maybe check with Schwab directly if you're affected, and/or try again today or at the weekend. I keep seeing messages in Schwab about data availability for tax download but they're not being very clear - originally the message was dated 2/25 but now it's dated today.
https://ttlc.intuit.com/community/taxes/discussion/re-why-can-t-i-import-my-charles-schwab-1099-into...
so many issues with Schwab this year, if this doesn't resolve you may just want to input manually and move on. Most 1099s are easily input esp R/INT/DIV. For 1099B you can input at summary level unless you have cost basis adjustments (wash sales, AMD, non-covered lots) those are best input at detailed level or you can send in the details using Form 8453 (TT Online also allows upload of PDF to satisfy this filing requirement).
