Can't add or save new products - error message

[ketbel]

Hi

I'm trying to add new products, but when I save the new products I got this error message:
call_user_func_array(): Argument #1 ($callback) must be a valid callback, class plgVmCustomTextinput does not have a method "plgVmOnStoreProduct"

How can I solve this problem?

[pinochico]

And do you drive a Volvo or a Skoda? (sarcasm)

What do you think you forgot?

[ketbel]

I'm not quite sure. 

[pinochico]

class plgVmCustomTextinput you find in plugin VmCustom/Textinput
Try disabled this plugin

And I think PHP8 is not for VM
And still VM 3.8.9 is beta version == not for production site

[Milbo]

Disabling the plugin is a good idea, if you do not use it anyway.

PHP 8 should work, we removed really a lot obstacles.
I think you missed to update also the PLugins. Just use this https://dev.virtuemart.net/attachments/1305/com_virtuemart.3.8.9.10622_package_or_extract.zip which is not beta anylonger.