I am using:
Org mode version 9.4.6 (9.4.6-2-g21eb69-elpa @ /Users/alanwehmann/.emacs.d/elpa/org-20210524/)
GNU Emacs 27.1 (build 1, x86_64-apple-darwin18.7.0, NS appkit-1671.60 Version 10.14.6 (Build 18G95)) of 2020-08-12
VM version is: 8.2.0b
org-plus-contrib-20210531 package
I have found emails (in VM) which have e.g. the following lines in them:
i.e. a line break after the colon.
This cannot be matched by the following code from function "org-vm-select-message" found in "ol-vm.el" from "org-plus-contrib-20210531":
(if (not (re-search-forward
(concat "^" "message-id: *" (regexp-quote message-id))))
(error "Could not find the specified message in this folder"))
The following change to this code works:
(if (not (re-search-forward
(concat "^" "message-id:\\s-*" (regexp-quote message-id))))
(error "Could not find the specified message in this folder"))
since "\\s-" matches white space, including line breaks.