When emailing participants the address for your survey or study it is strongly recommended that the address be placed on its own line with a blank line both above and below. Every effort should be made to avoid the address merging with surrouinding text.
For more information about survey addresses see:
Note that you should never email participants directly via Qualtrics. The Ethics Committee has mandated that no personal identifying information be stored offsite including in the Qualtrics servers. This includes email addresses.