How I can check I have travel ban

There are no portals or websites in the UAE that provide services to verify the existence of a travel ban. Rather, this is done through the police department by visiting the same person only; That is, you can check if there is a travel ban against you by visiting any police station yourself; However, this may put you at risk of arrest if there is an arrest warrant issued against you.
So, the safest way is to have a travel ban checked by a lawyer, in which case you will need to provide the lawyer with copies of your passport and power them on your behalf.