Having troubles with mapped network drive LaCie 5big Network 2
Hello! Please help me anyone. I have iMac 27" late 2009 running High Sierra. And I have Lacie 5big Network 2 with two 4TB disks in it, running as RAID 1. I've used Lacie to keep my GoPro videos and as iTunes Media folder. For 5 years I had no troubles (except one moment when one of the drives gone and I had to replace it, but I hadn't any troubles with it because of the RAID 1). Everything worked fine till last week. I used my Macbook on Catalina to transfer videoclips from SONY action cam to 5big, so I disconnected it from iMac and connected to Macbook. Transferred files easily, but when I re-connected 5big to iMac it started to act strange: when iMac is freshly booting network drive is accessible and I can work with my files, but after 10-15 imutes Finder shows "Can't access network drive or you have no rights to access it" (I translate from russian, so maybe in English this error message looks somehow else). But I haven't done anything to Lacie, one user and one share as always.
I can access drive via Lacie Network Assistant, and it shows the contents of the drive. But I can't access it from iMac, though I can see network drive mounted in the left panel of the Finder. I tried to use ForkLift or Moroshka file browsers instead of Finder, they have the same issue - network drive is seen, but not accessible.
I don't have any idea what to do and what happened:(( Please give me some advise.
iMac 27", macOS 10.13