Error writing a new invoice

I installed the system and everything works perfectly however,

When I generate a new invoice the option to insert more items does not work, I click the "+" button and nothing happens.

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I installed the system and everything works perfectly however,

However the system is not recording the invoices, it would normally output the other registers, but when I write an invoice does not work.

When I generate a new invoice the option to insert more items does not work, I click the "+" button and nothing happens.