Subscription update failed: check these six causes first

Updating a subscription is itself a network request, and it has to reach the provider's subscription URL first. So a failed update is often not a broken subscription — it is a request that never made it out.

1. The subscription URL itself is blocked

Not being able to reach the subscription domain without a tunnel is the most common case. Either connect to a node that still works and then update, or configure the subscription to fetch through the proxy. Some providers hand out several backup subscription domains; try another one.

2. The list goes empty after updating

That usually means the subscription answered, but with nothing in it. Most often the data allowance is used up, the plan expired, or the account was reset. Opening the subscription link in a browser to see what comes back is far faster than guessing inside the client.

3. The copied link picked up stray characters

Copying from a web page easily drags along a space or a line break. It looks fine when pasted, but the request goes to the wrong address. Delete it and copy again — and make sure you copied the subscription link and not the URL of the page showing it.

4. Wrong subscription format

Providers usually offer several formats. v2rayN and v2rayNG want the generic or V2Ray one, which is a base64-encoded list of share links. If you grabbed the Clash entry instead, the client receives YAML and cannot parse any servers out of it.

5. The system clock is off

A large clock skew makes TLS certificate validation fail, which shows up as every https request failing, subscription included. On Windows, open Date and time and press sync now.

6. Read the log

With the first five ruled out, open the log. Whether it is a timeout, a DNS resolution failure or a certificate error, the log says so plainly. See reading v2rayN logs, and importing a subscription for the basics.