The restrictions fall into three groups: what the bot accepts in the signal text, how long the signal is tracked, and which ceilings your trading settings and the exchange impose.
“Maximum simultaneous trades limit reached for bot "…". Signal from channel "…" skipped” — raise the limit or wait for trades to close.
“♻️ Duplicate signal for … from channel «…» skipped. There is already an active trade for this pair in the same direction — no second trade opened.” — see One signal per pair.
“trade amount … is below the exchange minimum for … — at least … is required. Increase the trade amount in bot settings” — raise the amount or the balance percentage.
“⛔ Signal trading is disabled for your account … The signal was received but no trade was opened. Please contact the administrator.” — an account restriction, resolved through support.
“⚠️ Too many requests. Please wait N sec. and try again.” — just wait, the account is not blocked.