I upload files for translation but the translators do not receive the files

Most of the time, whenever I have to upload a batch of translations for translation and I notify the translators of them, they usually receive only part of them, while the other files are left in limbo. Normally, what I usually do is to delete those files that have been uploaded perfectly, just like the others, and upload them again until they give me the OK that they have received them.
I don't understand why these things happen, I always upload all the files in the same way. They receive many of them, but many others do not.

What has also happened to me related to this is that I had put one of the members as the final checker and given him the "Final Check" function within Trados Live. He never received these documents for review, so I always had to re-upload the file translated by the translators and give him both the role of translator, linguistic reviewer and final check, in order to make sure that he has no problem to open the document and work with it.

Can you help me with this, do you have any idea why this might be happening or if there is something I am doing wrong?

Thanks in advance

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