... attribute "..." had invalid value "...." and has been replaced

Cause:

The attribute value is incorrect. For a color, the value must be a name like "black" or begin with a # like "#FF00FF".

Example:

Here the attribute bgcolor is a color, the value should begin with a "#"

Good<td bgcolor="FF00FF">
Good<td bgcolor="#FF00FF">

Solution:

Please check the type of the attribute and depending of his type, correct the value.

References: