Each answer names the cause; the link leads to the page that owns the detail.

• Why is Cargo Sites empty? It lists destinations for the cargo you are carrying, so with an empty hold it shows (no loaded cargo). See Radio Menu and Deliver Cargo.
• Why did my crate not deliver? Unloading with Drop loaded only sets crates down; use Cargo > Deliver. The destination also has to accept that cargo, and your aircraft has to be at its delivery point while you unload. See Deliver Cargo.
• Why were only some of my crates delivered? A Settlement takes no more project cargo than its largest Project still needs; the rest stays on the ground. See Cargo.
• Why was my crate refused at an airfield? An airfield's storage is shared by every cargo, and a full store refuses further crates. The crate stays on the ground. See Airfields.
• Can the C-130 deliver to a Hub? No. Airplanes cannot land on a helipad, so the C-130 stores at an airfield and a helicopter flies the last leg. See Aircraft and Airfields.
• Why is a Source empty or blocked? A Source produces on a cycle and pauses while its own warehouse is full. See Sources.
• Why can I not start a Project? A Regional Project needs a free slot in its region, the required site level and its cargo in the local Reserve. Site upgrades need no slot. See Build a Project and Projects.
• Where do I see current rumors? Type -tyc rumors in DCS chat, or switch on the RADAR layer on the Live Map. See Rumors.
• Why can I not hear the A/N signal? The aircraft must be inside the signal's range, and either SRS must be connected and tuned to the rumor's exact frequency and modulation, or the rumor must be picked under Navigation > A/N Receiver in the radio menu. See Map a Rumor and A/N Direction Finding.
• Why is a Settlement not recovering? Trust only climbs while that Settlement's own Food store is high, and only while somebody is flying. See Recover a Settlement and Trust.
• Does the world consume supply while nobody is online? No. Settlement Food consumption and Trust changes pause while nobody is flying an airplane or helicopter. One player creates the normal Settlement Food demand; more players raise that demand gradually. Sources and factories continue running; see Settlements and Trust.
• Why is my balance negative? Fees are charged even without enough credits. See Credits.
• Why can I not buy anything? Purchases need enough credits, a linked Discord account and the right building in the City you stand at. See Upgrades and DCSBot.
• Did I lose my upgrades? Only a loss of that aircraft type removes them, unless they were insured. See Aircraft Losses.
• Does progress survive a restart? Yes for the world: sites, stock, Projects and statistics persist. Crates left lying on the ground do not last. See Restarts.