When a trade does not execute as expected — unexpected fill prices, missing orders, slippage, or a stop loss that did not trigger where you anticipated — the cause almost always falls into one of the six categories below.
Most execution issues are not software bugs. Tradecopia replicates broker events — it does not control execution, fill prices, or slippage. Identifying the correct root cause is the fastest path to resolution.
You might be experiencing this if:
A trade on the leader didn't copy to one or more followers
Follower orders filled at a different price or size than the leader
An order went through on the leader but was rejected or missed on a follower
Something went wrong with replication but there's no obvious error showing
Stops or take profit orders behaved unexpectedly on follower accounts
Unsupported or partially supported order types
Using order types that Tradecopia does not fully support produces incomplete or inconsistent replication — the leader's order is sent but the follower receives a different structure, or the bracket does not copy correctly.
Common examples:
Stop-limit orders used as stop losses — only stop market is supported
Auto trailing stop loss orders
Double bracket or nested ATM strategies
See What ATM order types does Tradecopia support? for the full breakdown of supported and unsupported types.
Broker-level processing differences
The broker controls execution. Tradecopia sends the order instruction — the broker decides how and whether to fill it.
Common examples:
Partial fills — the broker fills part of the order, not all, causing a size mismatch between accounts
Order rejected due to margin, account restriction, or the instrument not being permissioned on that account
Fill price differs from expected due to broker routing, slippage during volatile conditions, or matching engine behaviour
When the broker outcome differs from the leader's, the difference appears in Tradecopia as a mismatch — but the cause is at the broker level.
Connection instability
A WebSocket drop or reconnect mid-session interrupts replication for accounts on the affected connection. Orders placed on the leader during the gap are not seen by Tradecopia and are not relayed to followers.
Common examples:
Brief connection drop during active trading — trades placed during the disconnection window are missed
Reconnect delay causing a fill event to arrive after the replication window closes
Network instability causing intermittent gaps rather than a full outage
The result is typically a pattern of missed trades that does not repeat consistently across sessions. See How broker API rate limits affect trade replication for related throughput constraints that can narrow the replication window during active sessions.
Pro desktop: Your local internet connection is the link between Tradecopia and your broker. A network drop on your machine stops replication for the duration of the outage.
Pro+ Lite and Pro+: Replication runs on Tradecopia's infrastructure, not your machine. Your own internet connection dropping does not interrupt replication. A server-to-broker connection issue at the infrastructure level could still cause a gap — if you suspect this, contact the Tradecopia support team.
Local machine or network issues
This root cause applies to Pro desktop only. Pro+ Lite and Pro+ run on Tradecopia's infrastructure — replication is not affected by your local machine's resources, network connection, or power state. If you are on a cloud plan and experiencing execution issues, skip this section.
On Pro desktop, Tradecopia runs on your machine. The local environment directly affects how quickly it processes and relays orders.
Common examples:
High CPU or RAM usage slowing order processing
Background applications — antivirus scans, downloads, system updates — competing for resources during a session
Wi-Fi instability; wired Ethernet is recommended for trading
Computer sleep mode or network adapter suspension interrupting a session mid-trade
The result appears as delayed replication, missed orders, or inconsistent behaviour that does not follow a clear pattern.
Session workflow patterns that cause divergence
Actions taken during a session that introduce position state inconsistencies or create conditions the copier cannot automatically reconcile.
Common examples:
Cancelling only the TP or SL leg of an ATM bracket independently, leaving the other leg orphaned
Placing manual trades on a follower account while the Position Reconciler is active
Running multiple trade copiers simultaneously on the same accounts
Modifying orders too close to market price
This is the most frequent workflow-related cause and warrants specific attention.
When a limit or stop order is modified to a price very close to the current bid/ask, the broker may reject or inconsistently process the modification. Because each broker processes independently, the leader's modification may be accepted while one or more followers receive a rejection — or vice versa.
The result is drift that cannot be auto-corrected: accounts hold different position states after the modification, and no subsequent fill event will realign them automatically.
To avoid this: use market orders when you are near price; avoid dragging orders within a tick or two of the current market.
How to diagnose an execution issue
When a trade does not execute as expected, work through this sequence:
Check the broker first — log into the affected follower account on the broker platform and review the order history. Rejection codes, unfilled orders, and partial fills are all visible there. If the broker shows the order was processed correctly, the issue is not at the replication layer
Match the symptom to a root cause category — use the six categories above to identify which type of issue you are dealing with, then follow the resolution steps for that category
Evaluate Tradecopia last — Tradecopia replicates broker events. If the broker received and confirmed the order, replication functioned correctly
Note: If the trade count and order actions match between the leader and follower — but fill prices differ — replication is functioning correctly. Fill price differences are broker-side outcomes.
If you have worked through these steps and cannot identify the cause, contact the Tradecopia support team with the affected account, broker, the order details, and a description of what you observed.
Related articles
How to prevent recurring replication issues and keep your accounts in sync — session habits that prevent these root causes from arising
What ATM order types does Tradecopia support? — full order type reference for root cause 1
How broker API rate limits affect trade replication — throughput constraints during high-activity sessions