The client found the response content type of ‘text / plain; charset = UTF-8 ’, but expected‘ text / xml ’

Hello
I get a Status error The client found the response content type of ‘text / plain; charset = UTF-8 ’, but expected‘ text / xml ’. Request failed with error message at the level of my clients
I am on a cms web server and the client version 2.255.3.0 php 7.4
at the level of the signal an error of the cms I get the element ZEROMQ in!
On the other hand I have the impression that the clients are functioning normally, maybe they take too long to download the data
In fact the resource.htm files. are still at (0%)
even if the client in sleep mode
What should i do to fix this error ans what are resource files for ?
thanks

one day later
On 10 clients two, show exception in run bad request and the 8 others show the error utf 8 xmds
knowing that I use the same version of player the same layout and the same pc.
I do not understand


and at the cms journal I have this

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