As the payment run function in Safe Financials is very resource-consuming since it tries to post a huge amount of invoices to multiple accounts at the same time.
It is therefore advised not to try running it when other users are busy in the system as it can cause deadlocks for either the users or the one running the payment run which could result in a system crash.
If the issue still occurs when attempting payment run without any users logged in, please contact your IT to look into this as it may be a network or VPN issue.