Why transactions can take time to confirm
Wallets do not confirm transactions. The miners of each coin's network do.
The most common cause is making transactions with too low miner fees. While there are any transactions on the network paying miners higher fees, they have no incentive to confirm the ones paying them low fees. Too many transactions being sent worldwide can cause fees to increase, so low-fee transactions have to wait longer.
The second most common cause is having previous unconfirmed transactions. Generally transactions must confirm in order. New transactions usually can't confirm while there are other before it still unconfirmed. A transaction will confirm when there are no other transactions on the network paying miners higher fees.
How to prevent transactions from staying unconfirmed
The best way it to properly set the fees at the time of sending. Coinomi allows you to choose how much to pay for miner fees. For coins that give you the 3 dynamic options (low, normal, high), we recommend choosing the "high" priority fees for faster confirmation. Fee suggestions cannot predict the future, so may not be appropriate in case of a very sudden increase in congestion. You are always free to select the "custom" fee option and set the value yourself if you know which value to use.
How to make an unconfirmed transaction confirm faster
You can find our dedicated page for speeding up transactions here: https://coinomi.freshdesk.com/support/solutions/articles/29000009773
How to cancel an unconfirmed transaction
Ethereum or token transactions: they can be canceled following the instructions here: https://coinomi.freshdesk.com/support/solutions/articles/29000009773.
Other coins: transactions of other coins cannot be canceled. Eventually they will confirm and successfully send the coins to the destination address. You can also open the wallet of the coin in Coinomi and at the top corner select "... / Resynchronize" once. If the unconfirmed transaction disappears, you can send it again with higher fees. If it doesn't disappear, try again the next day. This will only work for transactions that have been unconfirmed for weeks.