Order Notification Emails not being sent to customers

[DivineMercy]

Joomla! 3.9.10
VirtueMart 3.8.4

Email are not being sent to customers to notify them that they placed an order with us.

I cannot find a relevent setting to correct this - Any suggestions would be appreciated - Everything is up to date. I also use One Page Checkout extention.

[Jörgen]

Try without one page extension.
Has it ever worked ?
New site ?
Upgraded site ?

Jörgen