Sanctions prohibit by default and license by exception. General licenses cover defined categories automatically; everything else needs a specific license — an application OFAC grants or denies with essentially unreviewable discretion, which makes the drafting the whole game.
Licensing timelines vary wildly by program and workload, from weeks to the better part of a year; applications with genuine urgency should say so with evidence. Silence past any reasonable period is itself addressable — the delay toolkit does not stop at USCIS's door.
Receiving, facilitating, even approving can each be prohibited dealings — the analysis runs on the specific program's prohibitions before anything moves. Ask first; unwinding after is the expensive order.
Long silence is common; documented follow-ups, then escalation — including unreasonable-delay theories for extreme cases — is the ladder. Most applications do eventually get answered; the record you keep decides what 'eventually' costs you.
There's no formal appeal; reapplication with changed structure is the practical route, and judicial review of licensing discretion is steeply uphill. Draft the first application like it's the only one.