I wish I had more information, but I'm not the person having the issue. Sadly it is affecting my business...
E-mails that I send to a customer for some reason turn up completely blank. I use Thunderbird and they're using Outlook. I don't really see an issue there, so my only thought here is that maybe the information is getting lost in transit (but I have no idea how to verify that).
Other times, to the same customer, my e-mails are being labeled as spam, and for some reason they can't even access the e-mail. We're on their whitelist, but e-mail is still being labeled spam. I'm not sure if this is a client issue, or if it's a setting on their e-mail server, and it's labeling us as spam.
They currently have their tech person looking at the issue, but he hasn't veen able to come up with anything. This has been going on for about 6 months now, and he's only there part time.
At this point I'm ready to talk to the person acutally in charge of ther website / e-mail server, but need to know what questions to ask, and what I can look into on my own before I call.