Have difficulties witha certail language file of the CB Gallery Plugin - SOLVED

My environment:
version of cb gallery plugin: [color=#28a745 !important]2.5.1+build.2024.09.23.15.14.11.5855dde14[/color] 
Joomla version: 3.10.12.
CB version: 2.9.3+build.2024.09.10.14.21.57.794f9ce0d

Behaviour:
If I try to upload a file with a 'wrong' extension within a users gallery the following alert should be prompted (see below the 'responsible' language string):

 'FILE_UPLOAD_INVALID_UPLOAD_ONLY_EXTS' => 'Invalid file. Please upload only [extensions]!',

.... the problem is that the whole part of the substring '[extensions]' .... does not appear on the screen ..... it will be repaced by a blank.

If I override of the string, eg.:

'FILE_UPLOAD_INVALID_UPLOAD_ONLY_EXTS' => 'You tried to upload an invalid file type. Please upload only [extensions]!',

... I have the same issue, the override itself works but the subpart: '[extensions]' will again be replaced by a blanc ....
... so the result looks like this: "You tried to upload an invalid file type. Please upload only !'

..... can you please help?

reagards
 

That's for the server side message. Client side should be erroring before server side is reached. Client side uses the following.

Key: INVALID_FILE_EXTENSION_PLEASE_UPLOAD_ONLY_0_7d7e70
String:
Are you sure it's the server side message you're seeing?

Now I repeated the test scenario and it worked ..... the correct language string as specified in: 'INVALID_FILE_EXTENSION_PLEASE_UPLOAD_ONLY_0_7d7e70' appeared .... I don't know why this didn't work few days before ..... but anyway .... ticket can be closed and Thanks