Unable to send submissions to the server

I designed the questionnaires then uploaded on the Kobo account.
the questionnaire was shared with the field team to collect the data.
During the data collection, the team was able to send all the collected questionnaires before 16-December, but
the questionnaires were collected on 16th -Dec, they were not able to send them to me ( one message came up with the whole team which is: inserting the user-name and password) . with noted that I have not made any changes in the Kobo -settings

@suaad1, what did you collect your data with? Is it the KoBoCollect android app or is it through Enketo? Could you also share with the community the screenshot of your issue so that the community should also be able to understand your issue pictorially?