Do you think, if the Vero has a moment of power instability, network wouldn’t be effected??
First step try powering the drive, even though it’s SSD and “shouldn’t” need power. There is no way to really “disprove” if the power used by the drive, combine with other factors could effect the NIC. Vero has USB2, ergo lower limit of amps. Most external harddrives are built for USB3, where there is in the standard a higher limit for amps delivered.
What filesystem is on that drive? Depending on FS, there is different CPU loads for writing and that goes for network transfer protocol used as well. Which means CPU will consume different amounts of power, while having a external drive powered by Vero4k(+) at the same time can spell disaster.