 Estimating a parameter using Stats
 Redefining $f(x,y) = x \cdot y \cdot \sin(1/x)\cdot \sin(1/y)$
 Are reals with discrete metric a $F$ space.
 Conjectures on Twin Euler Bricks
 Actual change vs instantaneous change for multiple variables
 Cellular boundary map $d_{1}:H_{1}(X^{1},X^{0} \rightarrow H_{0}(X^{0})$ same as simplicial boundary map $\Delta_{1}X \rightarrow \Delta_{0}
 Regarding standard basis and coordinate vectors
 Help with the Plancherel measure and the norm, on $\mathbb{T}$ and $C_0 (\mathbb{T}) \cap L^1 (\mathbb{T})\}$ respectively.
 S→∃x.Q(x) ⊢ ∃x.(S→Q(x)): How to prove the validity of this sequent in predicate logic?
 Fourier transform of $\text{sech}^4(x)$.
 $r$regular graph with dimension $2$
 Embedding compactly in Lebesgue spaces
 Probability Mass Function and CDF of a function with random variables
 Inverse or approximation to the inverse of a sum of block diagonal and diagonal matrix
 Need help solving exponential linear equation used to compare the value of a fixed annuity vs. an increasing annuity
 A number theoretical problem related to inverse sum of divisors
 I'm stuck at integrating an arc length over a circle
 Examples of proper loops in $\mathbb{R}$
 Models having the same standard system
 Can the product of 4 distinct numbers be equal to a fourth power?
Issues with the Default Email address for bounces  authentication
CiviCRM 4.7.19 / Drupal 7.54
I am stuggeling with the setup of the default mail account in CiviCRM
(... /civicrm/admin/mailSettings?reset=1)
I have setup a IMAP mail account for processing bounced email. Receiving email in this mail account works using my mail client using information below.
Mail account info:
Email address: bounces@mydomain.org
Username: bounces@mydomain.org (ISP requires that the full email
address be used for the username)
Password: mypass
Server: mail.mydomain.org
Protocol: IMAP
SSL: is activated
.
CiviCRM (CiviMAIL) settings:
Name: Bounce processing
Server: mail.mydomain.org
Username: bounces <<<< should be full email addres:
bounces@mydomain.org
Password: mypass
Local part:
Email domain: mydomain.org
Return address:
Protocol: IMAP
Source:
Use SSL: checked
Used for: processing bounces
.
Results Cron Job 
Entiteit: job Actie: fetch_bounces
Summ

CiviMail doesn't concatenate the username to the servername, it just takes whatever you provide and tries to connect using those credentials.
But my guess is that the issue is unrelated to the username, since your error message is:
Failed to connect to the server: mail.mbrainingcentrum.com:993.
I'd guess that you've more likely got a firewall issue, or an SSL issue on your server.
You can test by manually trying to connect to your mail server, using e.g. the instructions here:
https://technet.microsoft.com/enus/library/aa995718(v=exchg.65).aspx
6 days ago