Upload FTP Failed

Good morning
I have a video surveillance system consisting of 15 cameras
7 Mx-VB3A-2-IR-VA Firmware version mb20240126SX
and 8 M26.
From 1 of the MOVEs I upload an image to a server via FTP and everything worked until April 24th.
Now if I go to upload via FTP it tells me that upload failed.
But if I configure one of the M26s the upload works normally.
I checked the settings and they are correct. User, Password, porta21 etc.
I also contacted the provider to understand if my IP was on a Black List and they confirmed that it was not.
Anyone else have the same problem?
Thank you