Error when set Unpaid invoice to Paid

Hi

whmcs : 5.1.2

I just upgraded and everything working fine except below issue.

When I Try to Add Payment to Invoice by clicking"Add Payment" button (Please see attached image) it shows Blank White page as the result except showing correct result page

However invoice marked as PAID, BUT Next Due date not update correctly to Next year

This is not a template / browser cache and I removed all those as soon as I complete the upgrade

can anyone help to find the issue / fix this issue

Thanks

inv.jpg

Attached Images

• inv.jpg (32.1 KB)