[Lorenc_]

Try debugging the whole code by putting print messages in between each statement:

pawn Код:

if(strcmp(cmd, "/c", true)==0)
{
    if(PlayerInfo[playerid][pClanMem] == 250) return SendClientMessage(playerid,c_r,"( ! ) You're not in a clan !");
    print("1");
    new string[250];
    new clanf = PlayerInfo[playerid][pClanMem];
    print("1");
    if(Clans[clanf][Front] == 1) {
    print("2");
        if(PlayerInfo[playerid][pClanMem] == PlayerInfo[playerid][pClanKey]) {
    print("2");
            format(string,sizeof(string),"( C ) Boss [%s]%s : %s",Clans[clanf][cName],PlayerName(playerid),cmdtext[3]);
        }
    print("2");
        else {
    print("2");
            format(string,sizeof(string),"( C ) [%s]%s : %s",Clans[clanf][cName],PlayerName(playerid),cmdtext[3]);
        }
    print("2");
        MessageToClan(playerid,GetPlayerColor(playerid),string);
        return 1;
    print("2");
    }
    else {
    print("3");
        if(PlayerInfo[playerid][pClanMem] == PlayerInfo[playerid][pClanKey]) {
    print("4");
            format(string,sizeof(string),"( C ) Boss %s[%s] : %s",PlayerName(playerid),Clans[clanf][cName],cmdtext[3]);
        }
        else {
    print("5");
            format(string,sizeof(string),"( C ) %s[%s] : %s",PlayerName(playerid),Clans[clanf][cName],cmdtext[3]);
        }
        MessageToClan(playerid,GetPlayerColor(playerid),string);
    }
    return 1;
}

Check how many ones it prints, twos, threes, fours and fives it prints. If it doesn't print any, check which section the code stops on.

I hope I made this clear.

pawn Код:

stock MessageToClan(playerid,color,const string[])
{
    for(new i; i < MAX_PLAYERS; i++)
    {
        if( IsPlayerConnected( i ) ) 
        {
            new clan = PlayerInfo[i][pClanMem];
            if(clan == PlayerInfo[playerid][pClanMem]) SendClientMessage(i, color, string);
        }
    }
    return 1;
}

Change to public if needed outside your gamemode.

Try that as well.