There are 4 common reasons why you may be experiencing the MT4 error 133 error on Social Trader Tools, 3 can be resolved by yourself on our platform and the other will involve contacting your broker.
The 3 most common reasons for the error are;
Investor password
This means you have added the follower (send to) account using your MT4/5 investor password. Trades cannot be opened/closed/modified when using the investor credentials. To resolve this error simply update the account with your full MT4/5 credentials. Go to accounts, press manage on the problematic account, visit login credentials and re-enter your new credentials.
Suffix
A suffix is a prefix appended to a symbol, for example, ".stt". Brokers can add suffixes to symbols for many reasons. When they add a suffix to their forex symbols, they often disable the normal symbols which will result in error 133 when you try to trade them. To resolve this error, simply add the forex suffix to your account. Go to accounts, press manage on the problematic account, visit forex suffix, scroll the list and find the suffix (for example .stt), add that to the suffix input box and press update.
Invalid account
An invalid account means you added the account with the wrong credentials or using the wrong broker server. Sometimes this can happen after an account has been connected successfully and the client has changed their MT4/5 password and not updated it on our system. To resolve this error, simply go to accounts, press manage on the problematic account, visit login credentials and re-enter your new credentials.
If the above solutions do not work, the error is likely on the broker's end. Contact your broker and they should be able to resolve the issue.