Accounting categories
Your accounting system organises everything into accounts. Yessort knows about products, orders and receipts. An accounting category is the join between the two: it says which account a particular kind of activity belongs in.
Without the mapping, Yessort knows a sale happened but not where to record it — which is why an unmapped category leaves entries held rather than posted.
How a mapping works
A category exists in Yessort, and is mapped to an account in the connected provider. The mapping is per provider, so the same Yessort category can point at different account codes in different systems.
The provider's chart of accounts is read from the connection, so you choose from your real accounts rather than typing codes and hoping.
Manual accounting has no chart of accounts to read, since there is no external system. Categories still exist and still organise your activity; there is simply nothing external to map them onto.
Sales revenue today
Worth being precise about, because it is easy to assume more control than exists.
Sales posting currently uses your organisation's default revenue account. Per-variant accounting categories are not yet wired into it, so setting a category on a variant does not currently change which revenue account its sales land in.
Categories are still worth setting — they organise your catalogue and are ready for when per-variant posting arrives — but do not expect a variant's category to split revenue across accounts today.
Where categories do decide the account
Other entries do resolve their account from configuration: the goods-receipt valuation journal, supplier bills and COGS. These are the ones that end up in Issues when the account is missing.
What happens when a mapping is missing
The entry is not built, and it is not lost. It is held, and released when you map the account — including the ones that were already waiting. See hold, don't drop.
So a stack of issues after connecting is normal, and it clears as you complete the mapping rather than needing to be worked through one at a time.