When attempting to upload or download file(s) to a folder in MOVEit Transfer, Live View shows the following status for the upload:  No data transmitted for 90 seconds

The upload or download fails. In some cases for a failed upload, an incomplete file will be in the target folder which cannot download (because it is incomplete), but it can be deleted.

Recommendation:

To confirm whether the issue is external from the Transfer server, take the following steps:
1. Access the Windows server that is hosting the MOVEit Transfer application.
2.Open a web browser and type https://localhost
3. Log in as administrator and attempt to upload/download one of the files that failed previously when trying it externally. A successful upload/download confirms that the issue is external to the Transfer server. This indicates efforts should be focused to the external environment (i.e. Load Balancer, Firewall, etc.).

Next Step:

This step is focusing on a F5 Load balancer. With the help of the network/security team, the F5 load balancer can be set to a LEARNING mode temporarily to troubleshoot the issue. This article from F5 talks about the learning mode option:
Refining Security Policies with Learning - https://techdocs.f5.com/kb/en-us/products/big-ip_asm/manuals/product/asm-implementations-12-1-0/23.html

Once the F5 is set to learning mode, attempt to upload/download the files again externally and see if it is now successful. If it is, that will mean that there were some security policies blocking the file upload/download previously when the failures occurred. At this point, the learning mode of the F5 should give the network/security teams enough information to set up the correct security policy to prevent the blockage of data traffic directed to MOVEit Transfer.

PLEASE NOTE: This type of adjustment is outside of the MOVEit Support team's scope. We do not make recommendations on security policies. We are providing these steps to help you during the troubleshooting phase. It is ultimately the responsibility of the network/security teams to set up the correct security policies on the F5 load balancer to allow all  legitimate data traffic directed to the Transfer application.