If you're facing an issue where after placing an order, it's stuck in "Payment pending" even though the payment did go through, it might be because Cloudflare is blocking PeachPay from reaching the store and updating the order status.
Here are two ways to add an exception for PeachPay in Cloudflare.
Allow all likely bot traffic
The easiest way to fix the issue is to navigate to Security / Bots / Likely automated and set it to Allow.
If you don't experience any bot issues, then keeping this setting on Allow should be okay. If not, continue reading to try a more specific exemption setting.
Exclude PeachPay from Cloudflare bot challenge with a rule
Follow Cloudflare's documentation to exempt PeachPay's API traffic from the Cloudflare firewall.
The rule you can use is
(cf.bot_management.score lt 30 and not cf.bot_management.verified_bot and not http.request.uri.path contains "peachpay"))
The important part to include is
not http.request.uri.path contains "peachpay" if you already have custom rules set.
After setting this, automated API traffic from PeachPay can reach your store, but all other bots will continue to be blocked.