CAS ban on Telegram: what it means, and what to do about a wrong one

What is a CAS ban?

CAS stands for Combot Anti-Spam. It is a shared list of Telegram accounts with a spam record, run by Combot, the community management bot. Its site, read on 13 October 2026, describes it as "an automated system designed to detect spammers in Telegram groups".

The idea: an account caught spamming in one group should not have to be caught again in the next. CAS's site says that when a user with any spam record joins a group protected by CAS, that user is banned immediately. Combot's site adds that this happens before the account posts anything.

Three things a CAS ban is not:

• It is not a ban from Telegram. CAS is not run by Telegram. The account keeps working.
• It is not a ban on a phone number. CAS's site says Combot does not know your phone number. The Telegram user ID is banned.
• It is not a ban by a group admin. CAS's site says group admins can ban users in their own group and report spam, but cannot add anyone to CAS.

Everything in this guide about CAS and Combot comes from cas.chat and combot.org as they read on 13 October 2026. Where those sites do not describe something, this guide says so. Missing documentation does not prove a feature is absent.

How does an account get on the CAS list?

CAS's site says the system detects spam "without human factor". The decision is automated. The site does not publish the rules it uses.

What it does publish is the record. On 13 October 2026, the entry for a banned account shows:

• the date and time the account was added,
• the number of registered offenses,
• the reason, such as spam,
• the text of the message that was recorded.

CAS also publishes a feed of its last 100 bans. On the day this guide was written, new entries appeared every minute.

Asked how to avoid a CAS ban, the site answers: "Don't spam." That does not cover an account that was taken over and used by someone else, which CAS treats the same way. See below.

How do I check whether an account is CAS banned?

1. Find the account's Telegram user ID. It is a number, not the @username. A bot that removed the member often shows the ID in its log or in its ban message.
2. Open the Query page on cas.chat and enter the number.
3. Read the result. A listed account shows the date, the offenses, the reason and the message. An account that is not listed shows no record.

Read the recorded message before you decide anything. It is the best evidence you have.

Developers can ask the same question through the CAS API, which has a check method that takes a user ID. On 13 October 2026 the API page says requests without a key are still accepted, and that keys will become required.

Which groups and bots use CAS?

CAS's site gives two answers. Any group that uses Combot can be protected by CAS. And developers can use the CAS API to build the check into their own bots. Combot's site calls CAS "free for everyone, and open to third-party bots".

That is why a member can be refused in a group that has never added Combot.

Bot	Does it check CAS?	Source
Combot	Yes. CAS is listed on every plan, the free plan included	Combot's site, 13 October 2026
Targa	Yes, together with federations	Targa's own feature list
Rose	Not documented. Rose documents federations, which are its own shared ban lists	Rose's documentation, 13 October 2026
Other bots	Ask, or look for a "Powered by CAS" note	CAS asks commercial services that use the list to link to cas.chat

"Not documented" means the documentation does not describe it. It does not prove the feature is absent. For what each of these bots does beyond ban lists, see the Combot guide and the Rose guide.

What does a CAS ban mean for a member?

In a group whose bot checks CAS, the account is banned on joining. In a supergroup a banned account goes on the group's Removed Users list, and it cannot rejoin through an invite link while it stays there.

Everywhere else, nothing changes. The account can still send private messages, post in channels and join groups that do not consult the list.

Do not confuse this with Telegram's own limits. When Telegram's moderators limit an account after spam reports, the account cannot write to strangers for a time, and Telegram's Spam FAQ sends the owner to its official @SpamBot. That is a separate system. A CAS ban does not limit private messages, and @SpamBot cannot lift it.

	CAS ban	Telegram spam limit	Ban by a group admin
Who decides	CAS, automatically	Telegram's moderators	The group's admins
Where it applies	Groups whose bot checks CAS	Across Telegram, for messages to strangers	That one group
Who can lift it	Nobody on request. It expires	Telegram, through @SpamBot	That group's admins

Can a CAS ban be appealed or removed?

CAS states its position at the top of its site: "CAS bans are non-negotiable, and cannot be removed by Combot community managers. CAS bans are removed automatically after some time."

Its page for banned users takes the hardest case directly. The question is: "I wasn't using my account when I received a CAS ban. Can it be removed?" The answer begins with "No." It says the ban cannot be removed on request, regardless of who was using the account, and that Combot keeps "a zero tolerance policy for spammers".

So, on 13 October 2026:

• There is no appeal form and no person who reviews a ban.
• The ban ends automatically. The site does not say after how long.
• CAS links to a public discussion group. It offers that as a place to talk about CAS, not as a way to get a ban lifted.

Two points should be stated plainly. The first is that this policy has a reason. A list that can be argued with gets argued with by every spammer on it, and review by people does not keep up with a feed that grows every minute. The second is that the policy has a cost. An automated list with no appeal will sometimes hold an account that should not be there, such as one that was stolen and later recovered. CAS does not publish how often this happens, and this guide does not guess.

If you are the member, there are three useful things to do. Check your record on the Query page so you know what was recorded. If the message is not yours, secure the account: what to do when a Telegram account is hacked. Then write to an admin of the group you want to join, explain what happened, and ask them to let you in. They can. CAS cannot be asked.

What can an admin do about a wrong CAS ban?

CAS is a list your bot consults. It does not own your group. CAS's own site says that whoever runs the group can ban users for any reason they choose. The same holds in the other direction.

1. Check the record first. Look up the user ID and read the recorded message. Decide whether you believe the member's account of it.
2. Exempt the member, if your bot can. Some bots let an admin approve or allow one account so that list checks no longer apply to it. Look in your bot's settings or documentation. Combot's and CAS's sites do not describe such a setting on 13 October 2026.
3. Or turn the CAS check off. CAS's wording is that a group using Combot "can be" protected by CAS, and Combot's plans list CAS as a feature. Neither site documents the switch itself, so look for it in your bot's settings. With the check off, your group no longer bans on the list at all.
4. Then lift the ban in Telegram. Take the account off Removed Users so it can join again. Do this after step 2 or 3. If the bot still checks CAS, it will ban the account again on the next join.
5. Watch the first messages. If you were wrong about the member, an ordinary ban takes a few seconds.

Turning the check off for one member has a price: you lose a filter that stops many known accounts before they post. If your bot can exempt a single account, prefer that.

Should my group use CAS at all?

For most groups, yes, as one filter among several.

What a shared list gives you: accounts already caught elsewhere are stopped before their first message, at no cost and with no setup.

What it cannot give you: a judgement on an account with no record. Spam accounts are bought new and thrown away, so many of them arrive with a clean record. And it cannot give you a way to correct the list itself. You can only correct what happens in your own group.

A reasonable arrangement is to keep the list, add something that judges what accounts actually post, and make sure an admin can see why each account was removed. How to protect a group from scammers covers the rest of the setup.

Targa works this way. It checks the CAS list and federations, which are ban lists that groups share with each other, and an AI reader checks every message and every edit. Every action carries a reason you can read with /why, and every action can be undone in one tap. If you want to watch it first, shadow mode removes nothing and logs what it would have done. Targa is in private beta, so access is by request. The plans list what each one includes.