Your broker rejected the order size. Three causes, in order of likelihood.
1. Below the minimum
Small equity plus a wide stop produces a size under the broker's minimum lot (often 0.01). The order cannot be placed at all.
- Raise risk per trade, or
- Use a micro/cent account where the minimum is smaller, or
- Skip signals with very wide stops on that channel.
2. Off the step size
Brokers accept sizes in increments — 0.01, or sometimes 0.1. PipSync rounds to the step, but if rounding down would land on zero, the trade is rejected instead of silently sized to nothing.
3. Above the maximum
Either your max lot cap or the broker's per-order ceiling. Large equity with a very tight stop hits this quickly. Check which limit fired — the log names it.
If a signal carried its own explicit lot size, that bypasses percentage sizing but is still capped by your max lot. That cap is the last thing standing between you and a provider's typo.