Error saving mail display name with comma: `mailbox display name is not valid`

[d19dotca]

I noticed that when I try to set an email display name for a Cloudron app like WordPress that it won't allow values with commas in it. I'm trying to set the legal business name, but for some reason this is not working. The error I see in the user interface is mailbox display name is not valid. Interesting it accepts the ampersand (&), but not the comma (,) characters.

Is this intended behaviour though? It seems like a defect to me because I can't imagine why commas are not valid "From Display Name" characters, but wanted to double-check. To my knowledge, commas are allowed in an email "From Name".

[ccfu]

The comma is a delimiter and can cause problems with some mailservers. Have you tried putting the name inside double quotes?

[d19dotca]

@ccfu I tried in double-quotes but there was no difference, still throws the same error. Single-quotes too.