Sometimes you may see errors on the Transaction Page under the Cost Basis column.
A cost basis that is marked as an error can have multiple causes:
Out of date cost basis - Make sure to click the "Update cost basis" button in the "Transactions" page to update all cost basis and fix missing ones.
Incorrect transactions history - If at some point the balance for an asset is negative, then cost basis errors will occur. Indeed our cost basis calculation algorithm strictly forbids spending money you don't actually have. Negative balances usually mean that the transaction history for a particular asset is incomplete and/or incorrect.
Missing valuation - If we are not able to value an asset, then we can not compute its cost basis.