[FEATURE] Add error handling

[YuriDevAT]

Description

As a user I want to perceive visually as well as acoustically that the tag I wanted to enter is not right or already in the list.

Screenshots

Color: B3261E

Additional information

No response

[CBID2]

Can I be assigned to this @YuriDevAT?

[YuriDevAT]

Can I be assigned to this @YuriDevAT?

I am afraid non of these issues are currently "ready for dev".

[CBID2]

Can I be assigned to this @YuriDevAT?

I am afraid non of these issues are currently "ready for dev".

Oh sorry @YuriDevAT! :) I’ve been wanting to contribute to your project again and thought this would be a good way to do it :)