On PDA toggle the Start | Settings | USB to PC | "Enable advanced network functionality" from checked to unchecked (or vice-versa) and see if that resolves the issue.
Try cleaning contacts on bottom of pda with a pencil eraser or a small amount of alcohol on a paper towel.
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HELPFUL SOLUTIONS FOR PDA ISSUES
These are instructions for assisting with common PDA issues or settings. See attached document "PDA_Helpful_Info_Rev-20201007.docx".
Resetting MC50, MC55, MC65, MC70, MC75
Performing a Warm Boot - A warm boot restarts the device by closing all running programs. MC 55,65,70,75: Hold down the red Power button for approximately five seconds. As soon as the device starts to boot release the Power button. MC 50: Press the ...