The suspense account contains any transactions that the system can’t match with a balancing entry. This includes opening balances and any untagged bank transactions.
The first starting point would be the bank account, in this case, for Stripe. Do you have an untagged entry there for around £400.00? If so, tagging it will remove the suspense account entry.
It’s worth remembering that with Stripe transactions (or any other payment provider for that matter), there are basically 3 transactions for every 1:
Money in from your client held by Stripe (A)
Money out for the Stripe fee (B)
Money out that Stripe deposits to your bank account (= A - B)
If you can rule out untagged entries, consider your opening balances - do you have any that you haven’t journaled on the system (e.g. if you used Stripe before QuickFile and Stripe was holding money of yours at the time).
If that didn’t prove to be successful, clicking on the speech bubble on the entry in the suspense account itself will often reveal more information about it’s origin.
The Stripe bank account should reflect your Stripe account itself. You would have:
Money coming in when the client pays (tagged to the invoice(s))
Money going out equal to the Stripe fee (tagged to the Stripe invoice when it’s issued)
Money going out equal to the balance which should match what they deposit into your bank account.
The second point is optional if you have quite a few transactions. It may be easier to let the balance accumulate until the end of the month and just pay off the Stripe invoice in full when it’s issued (which I believe is normally a few days into a month).