The PIN you have set in Jaxx is session and device dependent which means that the PIN does not transfer to other devices you have the wallet paired on and if you pair another wallet (or re-pair the same wallet) or re-install the application, the PIN will be deleted as well.
If you have forgotten your PIN, the simplest way to bypass it is by reinstall Jaxx and pairing it with the 12 word Backup Phrase.
Before doing this, to be sure you have the correct Backup Phrase, pair the wallet on another device first and check if the wallet addresses and balances match. (https://www.jaxx.io/downloads.html)
Once you are certain that you have the correct Backup Phrase, please delete your current Jaxx app then download it from https://jaxx.io/downloads.html . After it is installed, pair it with the Backup Phrase by clicking on Pair/Restore Wallet" instead of "Create New Wallet.
If you do not have your 12-word Backup Phrase, please know that as a security measure, we are not storing any wallet private information on any server. Jaxx is to be used as a decentralized wallet where only you have full control over your digital assets and we don't have a centralized way of managing the user's wallets like banks do.
What we have seen other users do is try the most common PINs they have used in the past or potentially try out all 4-digit pin combinations until they find the matching one. Entering a wrong PIN multiple times will not lock the devices or add delays to accessing the PIN feature.